Co-reporter:Yihuang Chen, Di Yang, Young Jun Yoon, Xinchang Pang, Zewei Wang, Jaehan Jung, Yanjie He, Yeu Wei Harn, Ming He, Shuguang Zhang, Guangzhao Zhang, and Zhiqun Lin
Journal of the American Chemical Society September 20, 2017 Volume 139(Issue 37) pp:12956-12956
Publication Date(Web):August 28, 2017
DOI:10.1021/jacs.7b04545
The ability to tailor the size and shape of nanoparticles (NPs) enables the investigation into the correlation between these parameters and optical, optoelectronic, electrical, magnetic, and catalytic properties. Despite several effective approaches available to synthesize NPs with a hollow interior, it remains challenging to have a general strategy for creating a wide diversity of high-quality hollow NPs with different dimensions and compositions on demand. Herein, we report on a general and robust strategy to in situ crafting of monodisperse hairy hollow noble metal NPs by capitalizing on rationally designed amphiphilic star-like triblock copolymers as nanoreactors. The intermediate blocks of star-like triblock copolymers can associate with metal precursors via strong interaction (i.e., direct coordination or electrostatic interaction), followed by reduction to yield hollow noble metal NPs. Notably, the outer blocks of star-like triblock copolymers function as ligands that intimately and permanently passivate the surface of hollow noble metal NPs (i.e., forming hairy permanently ligated hollow NPs with superior solubility in nonpolar solvents). More importantly, the diameter of the hollow interior and the thickness of the shell of NPs can be readily controlled. As such, the dimension-dependent optical properties of hollow NPs are scrutinized by combining experimental studies and theoretical modeling. The dye encapsulation/release studies indicated that hollow NPs may be utilized as attractive guest molecule nanocarriers. As the diversity of precursors are amenable to this star-like triblock copolymer nanoreactor strategy, it can conceptually be extended to produce a rich variety of hairy hollow NPs with different dimensions and functionalities for applications in catalysis, water purification, optical devices, lightweight fillers, and energy conversion and storage.
Co-reporter:James Iocozzia and Zhiqun Lin
Macromolecules July 11, 2017 Volume 50(Issue 13) pp:4906-4906
Publication Date(Web):June 21, 2017
DOI:10.1021/acs.macromol.7b01074
The development of a simple, low-cost, and robust route to soft nanocapsules is an ever-present hurdle and requirement for their promising use in drug encapsulation and delivery. To date, several elegant strategies for nanocapsule formation have emerged. However, some of them fall short of one or several of the requirements including stability, biocompatibility, antifouling, and low cost which ultimately limit their potential impact. Owing to its inherent biocompatibility, low cost, and high functionalization characteristics, hyperbranched polyglycerol (HPG) derivatives may offer a possible solution. Through esterification and azidation of HPG hydroxyl groups, an intriguing UV-cross-linkable HPG-azidomethylbenzoyl ester (denoted HPG-4-N3-MBE) is yielded. Over short irradiation periods, fairy uniform wholly polymeric HPG nanocapsules with diameters less than 100 nm can be formed which exhibit good stability due to abundant cross-linking primarily though nitrene–nitrene coupling to produce azo linkages rather than potentially reactive azidirine ring linkages. This work demonstrates the simple, low-cost, and robust type of chemistry needed for the practical development of polymer nanocapsule-based drug delivery/encapsulation, waste remediation, and surface antifouling strategies.
Co-reporter:Yue Wang, Huina Cui, Mingjing Zhu, Feng Qiu, Juan Peng, and Zhiqun Lin
Macromolecules December 26, 2017 Volume 50(Issue 24) pp:9674-9674
Publication Date(Web):December 12, 2017
DOI:10.1021/acs.macromol.7b02126
Poly(3-hexylselenophene) (P3HS) carries attractive advantages over their close analogue poly(3-hexylthiophene) (P3HT), including a stronger intermolecular interaction, a better interchain charge hopping, and a narrower bandgap. However, P3HS is much less studied compared to P3HT. Herein, we report on intriguing reversible phase transition between two different crystalline polymorphs (i.e., form I and II) in P3HS thin films with different molecular weights enabled by alternating thermal and solvent vapor annealing. More importantly, the phase transition kinetics and mechanism as well as the associated changes on molecular packing structures were also scrutinized. The correlation between different P3HS crystalline polymorphs and the resulting field-effect mobilities was explored for the first time. Our study provides an insight into P3HS crystallization and phase transition, thus entailing the use of polyselenophene-based materials for a wide range of optoelectronic applications.
Co-reporter:Chao Wang;Yuci Xu;Weihua Li
Langmuir August 9, 2016 Volume 32(Issue 31) pp:7908-7916
Publication Date(Web):2017-2-22
DOI:10.1021/acs.langmuir.6b01904
The influence of star-like architecture on phase behavior of star-like block copolymer under cylindrical confinement differs largely from the bulk (i.e., nonconfinement). A set of intriguing self-assembled morphologies and the corresponding phase diagrams of star-like (AB)f diblock copolymers with different numbers of arms f (i.e., f = 3, 9, 15, and 21) in four scenarios (ϕA = 0.3 and V0 > 0; ϕA = 0.3 and V0 < 0; ϕA = 0.7 and V0 > 0; and ϕA = 0.7 and V0 < 0 (where ϕA is the volume fraction of A block) and V0 < 0 and V0 > 0 represent that the pore wall of cylindrical confinement prefers the inner A block (i.e., A-preferential) and B block (i.e., B-preferential), respectively) were for the first time scrutinized by employing the pseudospectral method of self-consistent mean-field theory. Surprisingly, a new nanoscopic phase, that is, perforated-lamellae-on-cylinder (denoted PC), was observed in star-like (AB)3 diblock copolymer at ϕA = 0.3 and V0 > 0. With a further increase in f, a single lamellae (denoted L1) was found to possess a larger phase region. Under the confinement of A-preferential wall (i.e., V0 < 0) at ϕA = 0.3, PC phase became metastable and its free energy increased as f increased. Quite intriguingly, when ϕA = 0.7 and V0 > 0, where an inverted cylinder was formed in bulk, the PC phase became stable, and its free energy decreased as f increased, suggesting the propensity to form PC phase under this condition. Moreover, in stark contrast to the phase transition of C1 → L1 → PC (C1, a single cylindrical microdmain) at ϕA = 0.3 and V0 > 0, when subjected to the A-preferential wall (ϕA = 0.7), a different phase transition sequence (i.e., C1 → PC → L1) was identified due to the formation of a double-layer structure. On the basis of our calculations, the influence of star-like architecture on (AB)f diblock copolymer under the imposed cylindrical confinement, particularly the shift of the phase boundaries as a function of f, was thoroughly understood. These self-assembled nanostructures may hold the promise for applications as lithographic templates for nanowires, photonic crystals, and nanotechnology.
Co-reporter:Shiqiang Zhao, Zewei Wang, Yanjie He, Beibei Jiang, Yeuwei Harn, Xueqin Liu, Faqi Yu, Fan Feng, Qiang Shen, and Zhiqun Lin
ACS Energy Letters - New in 2016 2017 Volume 2(Issue 1) pp:
Publication Date(Web):December 9, 2016
DOI:10.1021/acsenergylett.6b00582
Interconnected nickel bicarbonate (Ni(HCO3)2) hollow spheres were produced and exploited for the first time as an anode of lithium ion batteries, delivering the 80th reversible capacity of 1442 mAh g–1 at a current rate of 100 mA g–1, which is 3.9 times the theoretical capacity of commercial anode graphite. The time-dependent study suggested a self-sacrificial templating formation mechanism that yielded intriguing interconnected hollow structures. X-ray photoelectron spectroscopy measurements on cycled electrodes indicated that both the deep oxidation of Ni2+ into Ni3+ and the reversible reactions in HCO3– accounted for the ultrahigh capacity of Ni(HCO3)2 in comparison to its generally accepted theoretical capacity of 297 mAh g–1. Morphological characterizations revealed that the interconnected hollow structures enabled the enhanced rate performance and cycling stability, compared to those of the solid counterpart, because of their larger contact areas with electrolyte and better buffering effect to accommodate the volume change.
Co-reporter:Yanjie He;Dr. Xinchang Pang;Dr. Beibei Jiang;Dr. Chaowei Feng;Yeu-Wei Harn;Dr. Yihuang Chen;Young Jun Yoon;Shuang Pan;Dr. Cheng-Hsin Lu;Yajing Chang; Mona Zebarjadi;Dr. Zhitao Kang; Naresh Thadhani; Juan Peng; Zhiqun Lin
Angewandte Chemie International Edition 2017 Volume 56(Issue 42) pp:13151-13151
Publication Date(Web):2017/10/09
DOI:10.1002/anie.201708381
Rationally designed star-like triblock copolymers that were prepared by atom transfer radical polymerization were used as nanoreactors for the synthesis of semiconducting hollow nanoparticles that are inaccessible by conventional synthetic approaches. In their Communication on page 12946 ff., Z. Lin and co-workers describe the preparation of uniform PbS and PbTe hollow nanoparticles according to this approach.
Co-reporter:Yanjie He;Dr. Xinchang Pang;Dr. Beibei Jiang;Dr. Chaowei Feng;Yeu-Wei Harn;Dr. Yihuang Chen;Young Jun Yoon;Shuang Pan;Dr. Cheng-Hsin Lu;Yajing Chang; Mona Zebarjadi;Dr. Zhitao Kang; Naresh Thadhani; Juan Peng; Zhiqun Lin
Angewandte Chemie International Edition 2017 Volume 56(Issue 42) pp:12946-12951
Publication Date(Web):2017/10/09
DOI:10.1002/anie.201706182
AbstractDespite impressive recent advances in the synthesis of lead chalcogenide solid nanoparticles, there are no examples of lead chalcogenide hollow nanoparticles (HNPs) with controlled diameter and shell thickness as current synthetic approaches for HNPs have inherent limitations associated with their complexity, inability to precisely control the dimensions, and limited possibilities with regard to applicable materials. Herein, we report on an unconventional strategy for crafting uniform lead chalcogenide (PbS and PbTe) HNPs with tailorable size, surface chemistry, and near-IR absorption. Amphiphilic star-like triblock copolymers [polystyrene-block-poly(acrylic acid)-block-polystyrene and polystyrene-block-poly(acrylic acid)-block-poly(3,4-ethylenedioxythiophene)] were rationally synthesized and exploited as nanoreactors for the formation of uniform PbS and PbTe HNPs. Compared to their solid counterparts, the near-IR absorption of the HNPs is blue-shifted owing to the hollow interior. This strategy can be readily extended to other types of intriguing low-band-gap HNPs for diverse applications.
Co-reporter:Yanjie He;Dr. Xinchang Pang;Dr. Beibei Jiang;Dr. Chaowei Feng;Yeu-Wei Harn;Dr. Yihuang Chen;Young Jun Yoon;Shuang Pan;Dr. Cheng-Hsin Lu;Yajing Chang; Mona Zebarjadi;Dr. Zhitao Kang; Naresh Thadhani; Juan Peng; Zhiqun Lin
Angewandte Chemie 2017 Volume 129(Issue 42) pp:13126-13131
Publication Date(Web):2017/10/09
DOI:10.1002/ange.201706182
AbstractDespite impressive recent advances in the synthesis of lead chalcogenide solid nanoparticles, there are no examples of lead chalcogenide hollow nanoparticles (HNPs) with controlled diameter and shell thickness as current synthetic approaches for HNPs have inherent limitations associated with their complexity, inability to precisely control the dimensions, and limited possibilities with regard to applicable materials. Herein, we report on an unconventional strategy for crafting uniform lead chalcogenide (PbS and PbTe) HNPs with tailorable size, surface chemistry, and near-IR absorption. Amphiphilic star-like triblock copolymers [polystyrene-block-poly(acrylic acid)-block-polystyrene and polystyrene-block-poly(acrylic acid)-block-poly(3,4-ethylenedioxythiophene)] were rationally synthesized and exploited as nanoreactors for the formation of uniform PbS and PbTe HNPs. Compared to their solid counterparts, the near-IR absorption of the HNPs is blue-shifted owing to the hollow interior. This strategy can be readily extended to other types of intriguing low-band-gap HNPs for diverse applications.
Co-reporter:Yanjie He;Dr. Xinchang Pang;Dr. Beibei Jiang;Dr. Chaowei Feng;Yeu-Wei Harn;Dr. Yihuang Chen;Young Jun Yoon;Shuang Pan;Dr. Cheng-Hsin Lu;Yajing Chang; Mona Zebarjadi;Dr. Zhitao Kang; Naresh Thadhani; Juan Peng; Zhiqun Lin
Angewandte Chemie 2017 Volume 129(Issue 42) pp:13331-13331
Publication Date(Web):2017/10/09
DOI:10.1002/ange.201708381
Sternförmige Triblockcopolymere, die durch radikalische Atomtransferpolymerisation erhalten wurden, wurden als Nanoreaktoren für die Synthese hohler Halbleiter-Nanopartikel verwendet, die mit herkömmlichen Verfahren nicht herzustellen sind. In der Zuschrift auf S. 13126 ff. beschreiben Z. Lin et al. die Synthese gleichmäßiger hohler Nanopartikel aus PbS und PbTe nach dieser Strategie.
Co-reporter:Ruiping Liu, Weiming Su, Chao Shen, James Iocozzia, Shiqiang Zhao, Kunjie Yuan, Ning Zhang, Chang-an Wang, Zhiqun Lin
Materials Research Bulletin 2017 Volume 96, Part 4(Volume 96, Part 4) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.materresbull.2017.03.004
•Hollow SnO2 spheres were synthesized by NaF via employing hydrothermal method.•The microstructure of hollow spheres can be judiciously controlled by adjusting the amount of NaF.•Their high capacity reversibility and long-term cycling stability were demonstrated.•Their excellent rate performance was also exhibited.Hollow SnO2 spheres with oriented cone-like SnO2 nanoparticle shells were synthesized by a one-step hydrothermal process using NaF as the morphology controlling agent. The resulting hollow SnO2 sphere electrode exhibits high reversible capacity (initial charge and discharge capacities of 1342.9 and 1947.6 mAh/g at 0.1 C and 1235.4 and 1741.3 mAh/g at 1 C) and good cycling stability (discharge capacities maintained 758.1 and 449.6 mAh/g after 100 cycles at 0.1 C and 1 C, respectively). Good rate performance was also obtained (1234.5 mAh/g at 0.1 C, 884.2 mAh/g at 0.2 C, 692.4 mAh/g at 0.5 C, 497.6 mAh/g at 1 C, 315.8 mAh/g at 2 C and 80.6 mAh/g at 5 C, and more importantly, when the current density returns to 0.1 C, a capacity of 869.6 mAh/g can be recovered. The observed electrochemical performance can attributed to the hollow structure, the use of NaF for morphology control and the unique oriented cone-like shell of the particles.Download high-res image (170KB)Download full-size image
Co-reporter:Lan Sun;Zhi Wu;Siwan Xiang;Jiangdong Yu;Yingying Wang;Changjian Lin
RSC Advances (2011-Present) 2017 vol. 7(Issue 28) pp:17551-17558
Publication Date(Web):2017/03/17
DOI:10.1039/C6RA27388B
TiO2 nanotube arrays (TNTAs) were decorated with NiO nanoparticles via a sequential chemical bath deposition (CBD) approach to yield NiO@TNTA photoanodes. In sharp contrast to pure TNTAs, NiO@TNTAs displayed increased absorption and decreased photoluminescence. Interestingly, NiO@TNTA photoanodes exhibited a higher photoelectrochemical activity for hydrogen production than pure TNTAs. The incident-photon-to-current-conversion efficiency (IPCE) of the optimized NiO@TNTA photoanode was calculated to be 62.8%, and remarkably, the maximum hydrogen production rate reached 37.8 μmol h−1 cm−2, approximately 5.0 times faster than pure TNTAs. Such markedly enhanced photoelectrochemical efficiency can be attributed primarily to the efficient separation of photogenerated charge carriers at the p–n junction of the two dissimilar semiconductors, that is, p-type NiO and n-type TiO2, in conjunction with the implementation of nanosized NiO particles with large surface area which enables a shortened charge transfer distance and in turn increased probability of reaction of charge carriers with water molecules.
Co-reporter:Ping Ye;Xinling Liu;James Iocozzia;Yupeng Yuan;Lina Gu;Gengsheng Xu
Journal of Materials Chemistry A 2017 vol. 5(Issue 18) pp:8493-8498
Publication Date(Web):2017/05/10
DOI:10.1039/C7TA01031A
Nickel phosphide (Ni2P) was grown on a graphitic carbon nitride (g-C3N4) surface by annealing a mixture of g-C3N4, NiCl2, and NaH2PO2 at 400 °C for 2 h in an Ar atmosphere. During the annealing, Ni2P particles formed intimate interfaces with g-C3N4. As a result, charge transfer from photo-excited g-C3N4 to Ni2P was improved as demonstrated by the improved photocatalytic H2 generation (40.5 μmol h−1 g−1) compared to a physical mixture of Ni2P and g-C3N4 (trace H2 generation). Under optimal and identical experimental conditions, the H2 production rate on Ni2P-loaded g-C3N4 (2 wt%) is 82.5 μmol h−1 g−1, which is higher than that of Pt-loaded g-C3N4 (0.5 wt%) (72 μmol h−1 g−1). Impressively, Ni2P shows a highly stable H2 production activity despite being a non-noble metal co-catalyst. No activity loss occurs over repeated use and 24 h long-term H2 generation trials. In contrast, a pronounced reduction in H2 generation was observed for Pt-loaded g-C3N4 (0.5 wt%) over the same 24 hour trial period. Among their many advantages, including non-toxicity, low cost and natural abundance, Ni2P/g-C3N4 composites are a promising alternative for realizing efficient, long-lasting photocatalytic H2 production.
Co-reporter:Wentao Xu;Ping Ye;James Iocozzia;Hefeng Zhang;Yupeng Yuan
Journal of Materials Chemistry A 2017 vol. 5(Issue 41) pp:21669-21673
Publication Date(Web):2017/10/24
DOI:10.1039/C7TA07544H
Herein, we report a facile and rapid dry route rather than a solution process to prepare crystalline CdS nanoparticles via microwave-assisted thermolysis of a Cd-thiourea complex. CdS prepared by 35 min microwave heating offers a H2 generation rate of 103.2 μmol h−1 that is comparable to the H2 generation rate of commercially available CdS (96.3 μmol h−1). Importantly, the present synthetic strategy can be generalized to prepare other metal sulfides, including ZnS and MoS2, and ZnS–CdS solid solutions.
Co-reporter:Xilin Li;Kun Qian;Yan-Bing He;Cheng Liu;Decheng An;Yiyang Li;Dong Zhou;Baohua Li;Quan-Hong Yang;Feiyu Kang
Journal of Materials Chemistry A 2017 vol. 5(Issue 35) pp:18888-18895
Publication Date(Web):2017/09/12
DOI:10.1039/C7TA04415A
The ability to judiciously utilize gel-polymer electrolytes (GPEs) that replace liquid electrolytes is widely recognized as an attractive route to solving the safety concerns of Li-ion batteries (LIBs). In this context, novel LiNi0.8Co0.15Al0.05O2 (NCA)/graphite GPE and NCA/graphite–Si/C GPE batteries with high energy density and excellent electrochemical and safety performances are developed via in situ polymerization of pentaerythritol tetraacrylate (PETEA) in a liquid electrolyte. Notably, the capacity retention of NCA/graphite and NCA/graphite-Si/C GPE batteries after 200 cycles at the discharge rate of 5C is 92.5% and 81.2%, respectively, which are much larger than those implementing liquid electrolytes (i.e., only 55.9% and 51.4%, respectively). Interestingly, the GPE batteries also displayed considerably lower gas production, especially the graphite-Si/C anode battery, and did not undergo a violent combustion during the nail penetration test compared to the liquid electrolyte batteries. The markedly enhanced performances noted above can be attributed to the three-dimensional framework of the GPE which promoted the formation of a very tight protective film on the surface of the electrodes during cycling, thereby inhibiting the cyclable Li consumption and side reactions with the electrolyte. Furthermore, such a protective film effectively retained the structural integrity of the electrodes during the cycling process and reduced the heat reactions between the electrodes and electrolyte.
Co-reporter:Mengye Wang;James Iocozzia;Lan Sun;Changjian Lin
Energy & Environmental Science (2008-Present) 2017 vol. 10(Issue 9) pp:2041-2041
Publication Date(Web):2017/09/13
DOI:10.1039/C7EE90043K
Correction for ‘Inorganic-modified semiconductor TiO2 nanotube arrays for photocatalysis’ by Mengye Wang et al., Energy Environ. Sci., 2014, 7, 2182–2202.
Co-reporter:Xueqin Liu;James Iocozzia;Yang Wang;Xun Cui;Yihuang Chen;Shiqiang Zhao;Zhen Li
Energy & Environmental Science (2008-Present) 2017 vol. 10(Issue 2) pp:402-434
Publication Date(Web):2017/02/15
DOI:10.1039/C6EE02265K
The controlled synthesis of nanohybrids composed of noble metals (Au, Ag, Pt and Pd, as well as AuAg alloy) and metal oxides (ZnO, TiO2, Cu2O and CeO2) have received considerable attention for applications in photocatalysis, solar cells, drug delivery, surface enhanced Raman spectroscopy and many other important areas. The overall architecture of nanocomposites is one of the most important factors dictating the physical properties of nanohybrids. Noble metals can be coupled to metal oxides to yield diversified nanostructures, including noble metal decorated-metal oxide nanoparticles (NPs), nanoarrays, noble metal/metal oxide core/shell, noble metal/metal oxide yolk/shell and Janus noble metal–metal oxide nanostructures. In this review, we focus on the significant advances in tailored nanostructures of noble metal–metal oxide nanohybrids. The improvement in performance in the representative solar energy conversion applications including photocatalytic degradation of organic pollutants, photocatalytic hydrogen generation, photocatalytic CO2 reduction, dye-sensitized solar cells (DSSCs) and perovskite solar cells (PSCs) are discussed. Finally, we conclude with a perspective on the future direction and prospects of these controllable nanohybrid materials.
Co-reporter:Mingzheng Ge, Jingsheng Cai, James Iocozzia, Chunyan Cao, ... Zhiqun Lin
International Journal of Hydrogen Energy 2017 Volume 42, Issue 12(Volume 42, Issue 12) pp:
Publication Date(Web):23 March 2017
DOI:10.1016/j.ijhydene.2016.12.052
•State-of-the-art development on the fabrication of various TiO2 materials is reviewed.•Heterogeneous structures are designed by various strategies for enhanced H2O splitting activity.•Challenge and perspective on TiO2 materials are stated for efficient H2 production.Hydrogen is an attractive alternative to fossil fuels that addresses several environmental and energy shortage issues. Nano-sized TiO2-based photocatalysts with unique structural and functional properties are the most extensively studied photocatalytic nanomaterials for hydrogen production and pollutant degradation. However, titania is hampered by a wide band gap, low utilization of solar light and a rapid recombination of electron/hole pairs. These issues limit its photocatalytic performance. In this review, we present the latest developments in the fabrication of different higher dimensional TiO2 nanostructured materials that aim to address these inherent limitations to an otherwise very promising material. Specifically, we will look into critical engineering strategies to enlarge the active surface area, enhance visible light absorption and suppress the recombination of electrons/holes that benefit their photo/photoelectric-catalytic water splitting activity. Finally, the current challenges and perspectives for TiO2 nanostructures are also discussed. Continuous efforts are necessary to endow TiO2-based materials with novel advanced functionality and commercialization potential in the coming years.The state-of-the-art development of fabrication method on 0D, 1D, 2D and 3D TiO2 nanostructures is reviewed first. And then we will look into some critical engineering strategies to enlarge the active surface area, enhance visible light absorption and suppress the recombination of electrons/holes that benefit their photo/photoelectro-catalytic water splitting activity.Download high-res image (286KB)Download full-size image
Co-reporter:Jaehan Jung, Young Jun Yoon and Zhiqun Lin
Nanoscale 2016 vol. 8(Issue 16) pp:8887-8898
Publication Date(Web):28 Mar 2016
DOI:10.1039/C6NR00269B
Semiconducting organic–inorganic nanocomposites were judiciously crafted by placing conjugated polymers in intimate contact with inorganic tetrapods via click reaction. CdSe tetrapods were first synthesized by inducing elongated arms from CdSe zincblende seeds through seed-mediated growth. The subsequent effective inorganic ligand treatment, followed by reacting with short bifunctional ligands, yielded azide-functionalized CdSe tetrapods (i.e., CdSe–N3). Finally, the ethynyl-terminated conjugated polymer poly(3-hexylthiophene) (i.e., P3HT–) was tethered to CdSe–N3 tetrapods via a catalyst-free alkyne–azide cycloaddition, forming intimate semiconducting P3HT–CdSe tetrapod nanocomposites. Intriguingly, the intimate contact between P3HT and CdSe tetrapod was found to not only render the effective dispersion of CdSe tetrapods in the P3HT matrix, but also facilitate the efficient electronic interaction between these two semiconducting constituents. The successful anchoring of P3HT chains onto CdSe tetrapods was substantiated through Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy measurements. Moreover, the absorption and photoluminescence studies further corroborated the intimate tethering between P3HT and CdSe tetrapods. The effect of the type of bifunctional ligands (i.e., aryl vs. aliphatic ligands) and the size of tetrapods on the device performance of hybrid organic–inorganic solar cells was also scrutinized. Interestingly, P3HT–CdSe tetrapod nanocomposites produced via the use of an aryl bifunctional ligand (i.e., 4-azidobenzoic acid) exhibited an improved photovoltaic performance compared to that synthesized with their aliphatic ligand counterpart (i.e., 5-bromovaleric acid). Clearly, the optimal size of CdSe tetrapods ensuring the effective charge transport in conjunction with the good dispersion of CdSe tetrapods rendered an improved device performance. We envision that the click-reaction strategy enabled by capitalizing on two consecutive effective ligand exchanges (i.e., inorganic ligand treatment and subsequent bifunctional ligand exchange) to yield intimately connected organic–inorganic nanocomposites provides a unique platform for developing functional optoelectronic devices.
Co-reporter:Songping Wu, Zhuolin Wang, Xin Ouyang and Zhiqun Lin
Nanoscale 2016 vol. 8(Issue 12) pp:6884-6884
Publication Date(Web):04 Mar 2016
DOI:10.1039/C6NR90026G
Correction for ‘Core–shell Zn2GeO4 nanorods and their size-dependent photoluminescence properties’ by Songping Wu et al., Nanoscale, 2013, 5, 12335–12341.
Co-reporter:Mengye Wang, Xinchang Pang, Dajiang Zheng, Yanjie He, Lan Sun, Changjian Lin and Zhiqun Lin
Journal of Materials Chemistry A 2016 vol. 4(Issue 19) pp:7190-7199
Publication Date(Web):18 Mar 2016
DOI:10.1039/C6TA01838F
The ability to synthetically tune the size, shape, composition and architecture of inorganic nanostructures offers enormous opportunities to explore the fundamental structure–property relationships that occur uniquely at the nanoscale, and engineer greater functionality and design complexity into new material systems. Core/shell nanoparticles represent an important class of nanostructured materials that have garnered considerable interest. The success in producing core/shell nanoparticles with strictly controlled core diameter and shell thickness and tailoring their material properties relies crucially on the epitaxial growth of the shell material over the highly curved surface of the spherical core. However, effective methods to yield such high-quality core/shell nanoparticles are comparatively few and limited in scope. Here, we develop a robust nonepitaxial growth strategy to create uniform plasmonic/semiconducting core/shell nanoparticles with precisely controlled dimensions by capitalizing on amphiphilic star-like triblock copolymers as nanoreactors. The diameter of the plasmonic core and the thickness of the semiconductor shell can be independently and precisely regulated by tailoring the molecular weights (i.e., the lengths) of the inner and intermediate blocks of star-like triblock copolymers, respectively. The successful crafting of plasmonic/semiconducting core/shell nanoparticles was corroborated by the composition and structural characterizations. These functional nanoparticles exhibited largely improved photocatalytic activities, which can be attributed to the localized surface plasmon-mediated light harvesting enhancement of the plasmonic core and the built-in internal electric field. This nonepitaxial growth strategy offers new levels of tailorability in the dimensions, compositions and architectures of nanomaterials with engineered functionalities for applications in catalytic, electronic, optic, optoelectronic and sensory materials and devices.
Co-reporter:Cuiping Han, Yan-Bing He, Shuan Wang, Chao Wang, Hongda Du, Xianying Qin, Zhiqun Lin, Baohua Li, and Feiyu Kang
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 29) pp:18788-18796
Publication Date(Web):June 27, 2016
DOI:10.1021/acsami.6b04239
The ability to enhance the specific capacity of Li4Ti5O12 (LTO) is of practical significance and offers the opportunity to increase the energy density of a full LTO-based battery. Widening the discharge cutoff voltage to 0 V is an effective way to increase the capacity of LTO at low current density. However, whether the specific capacity of LTO at large current rates can be enhanced remains largely unknown. Herein, intriguingly, we found that, when cycled down to 0 V (i.e., from 1.0−2.5 to 0−25 V), LTO exhibited greatly enhanced specific capacity at low rates (<5 C), while it showed a rapid capacity fading and a greatly increased charge/discharge potential gap at high rates (>10 C). The decreased lithium-ion diffusion caused by extra lithium-ion intercalation together with increased internal impedance significantly enhances the polarization and reduces the electrochemical reaction kinetics, which, in turn, hinders the lithiation reaction from LTO to Li7Ti5O12 and further to Li9Ti5O12.
Co-reporter:Mengye Wang;Meidan Ye;James Iocozzia;Changjian Lin
Advanced Science 2016 Volume 3( Issue 6) pp:
Publication Date(Web):
DOI:10.1002/advs.201600024
Plasmonics has remained a prominent and growing field over the past several decades. The coupling of various chemical and photo phenomenon has sparked considerable interest in plasmon-mediated photocatalysis. Given plasmonic photocatalysis has only been developed for a relatively short period, considerable progress has been made in improving the absorption across the full solar spectrum and the efficiency of photo-generated charge carrier separation. With recent advances in fundamental (i.e., mechanisms) and experimental studies (i.e., the influence of size, geometry, surrounding dielectric field, etc.) on plasmon-mediated photocatalysis, the rational design and synthesis of metal/semiconductor hybrid nanostructure photocatalysts has been realized. This review seeks to highlight the recent impressive developments in plasmon-mediated photocatalytic mechanisms (i.e., Schottky junction, direct electron transfer, enhanced local electric field, plasmon resonant energy transfer, and scattering and heating effects), summarize a set of factors (i.e., size, geometry, dielectric environment, loading amount and composition of plasmonic metal, and nanostructure and properties of semiconductors) that largely affect plasmonic photocatalysis, and finally conclude with a perspective on future directions within this rich field of research.
Co-reporter:Sidney T. Malak;Jaehan Jung;Young Jun Yoon;Marcus J. Smith;Chun Hao Lin;Vladimir V. Tsukruk
Advanced Optical Materials 2016 Volume 4( Issue 4) pp:608-619
Publication Date(Web):
DOI:10.1002/adom.201500670
A facile one-step fabrication of large-area multicolored emissive photopatterns in mixed quantum dot-polymer films is demonstrated. This is in sharp contrast to the current photopatterning approaches that utilize only a single quantum dot (QD) component for single-color patterns. Strategies are presented that allow for either selective or collective modification of specific predetermined photoluminescent peaks of green and red QDs during photopattern development. These strategies yield novel patterns and allow for unprecedented control over how the color contrast of the photopattern evolves with continuous light illumination. These results clearly show that the evolution of the emission spectra of a multicolor mixed QD-polymer film can be readily tailored during pattern development, either by careful selection of the excitation wavelength or through combinations of controllably unstable and stable QDs with different recovery rates. Notably, these strategies are simple, fast, and robust, yielding high-resolution microscopic patterns over large areas (up to fractions of a cm2). Furthermore, the flexibility and capabilities of these strategies greatly expand the potential applications of multicolor emissive photopatterns, particularly in the areas of sensing, imaging, and lasing systems where it is important to exert delicate control over the intensity of selected colors within specific spatial regions.
Co-reporter:James Iocozzia and Zhiqun Lin
Langmuir 2016 Volume 32(Issue 28) pp:7180-7188
Publication Date(Web):June 30, 2016
DOI:10.1021/acs.langmuir.6b01830
Hyperbranched polyglycerol-block-polystyrene copolymers, denoted HPG-b-PS, are synthesized and employed as a new and effective unimolecular template for synthesizing colloidal gold (Au) nanoparticles. The coordination of noble metal precursors with polyether within the inner HPG core and subsequent in situ reduction enables the formation of well-dispersed and stable PS-capped Au nanoparticles. The inner HPG core is produced via ring opening multibranching polymerization (ROMBP) and subsequently converted into atom transfer radical polymerization (ATRP) macroinitiators for the controlled growth of polystyrene (PS) arms possessing low polydispersity (PDI < 1.31). An initial investigation into the templating parameters of HPG-b-PS was undertaken by producing templates with different arm numbers (98 and 117) and different PS chain lengths (i.e., molecular weight = 3500–13400 g/mol). It was found that the PS chain length and solvent conditions affect the quality of the resulting PS-capped colloidal Au nanoparticles. This work demonstrates, for the first time, a simple, lower-cost approach for templating nonpolar solvent-soluble PS-capped Au nanoparticles on the order of 10–30 nm in diameter.
Co-reporter:Beibei Jiang, Cuiping Han, Bo Li, Yanjie He, and Zhiqun Lin
ACS Nano 2016 Volume 10(Issue 2) pp:2728
Publication Date(Web):January 19, 2016
DOI:10.1021/acsnano.5b07806
The ability to create a synergistic effect of nanostructure engineering and its hybridization with conductive carbonaceous material is highly desirable for attaining high-performance lithium ion batteries (LIBs). Herein, we judiciously crafted ZnFe2O4/carbon nanocomposites composed of ZnFe2O4 nanoparticles with an average size of 16 ± 5 nm encapsulated within the continuous carbon network as anode materials for LIBs. Such intriguing nanocomposites were yielded in situ via the pyrolysis-induced carbonization of polystyrene@poly(acrylic acid) (PS@PAA) core@shell nanospheres in conjunction with the formation of ZnFe2O4 nanoparticles through the thermal decomposition of ZnFe2O4 precursors incorporated within the PS@PAA nanospheres. By systematically varying the ZnFe2O4 content in the ZnFe2O4/carbon nanocomposites, the nanocomposite containing 79.3 wt % ZnFe2O4 was found to exhibit an excellent rate performance with high capacities of 1238, 1198, 1136, 1052, 926, and 521 mAh g–1 at specific currents of 100, 200, 500, 1000, 2000, and 5000 mA g–1, respectively. Moreover, cycling performance of the ZnFe2O4/carbon nanocomposite with 79.3 wt % ZnFe2O4 at specific currents of 200 mA g–1 delivered an outstanding prolonged cycling stability for several hundred cycles.Keywords: advanced anode; continuous carbon network; lithium-ion batteries; ZnFe2O4 nanoparticles;
Co-reporter:Yingkui Yang, Cuiping Han, Beibei Jiang, James Iocozzia, Chengen He, Dean Shi, Tao Jiang, Zhiqun Lin
Materials Science and Engineering: R: Reports 2016 Volume 102() pp:1-72
Publication Date(Web):April 2016
DOI:10.1016/j.mser.2015.12.003
Intensive interest in graphene has centered on its unique 2D crystal lattice and remarkable properties that offer unique opportunities to address ever-increasing global energy demands. The past years have witnessed considerable advances in the fabrication of graphene-based materials and significant breakthroughs in advanced energy applications. In this Review, two methodologies for graphene production, namely, the bottom-up growth from hydrocarbon precursors and the top-down exfoliation of graphite (to graphene) and graphite oxide (to graphene oxide followed by reduction) are first summarized. The advantages and disadvantages of these methods regarding their accessibility, scalability, graphene quality, and inherent properties are compared. Particular attention is concentrated on tailored nanostructures, electronic properties, and surface activities of these intriguing materials. The preparation of graphene-based composites containing a wide range of active constituents (e.g., transition metals, metal oxides, and conducting polymers) by in-situ hybridization and ex-situ recombination is also discussed with an emphasis on their microstructures and hybrid architectures. This Review is devoted largely to current developments of graphene and its derivatives and composites in energy conversion (i.e., polymer solar cells, dye-sensitized solar cells, perovskite solar cells, and fuel cells) and energy storage (i.e., lithium-ion batteries and supercapacitors) on the basis of their intrinsic attributes in improving photovoltaic and electrochemical performance. By critically evaluating the relationship between the nanostructures and the device performance, we intend to provide general guidelines for the design of advanced graphene-based materials with structure-to-property tailored toward specific requirements for targeted energy applications. Lastly, the potential issues and the perspective for future research in graphene-based materials for energy applications are also presented. By summarizing the current state-of-the-art as well as the exciting achievements from laboratory research, this Review aims to demonstrate that real industrial applications of graphene-based materials are to be expected in the near future. (1346 references).
Co-reporter:Xinchang Pang;Yanjie He;Jaehan Jung
Science 2016 Volume 353(Issue 6305) pp:1268-1272
Publication Date(Web):16 Sep 2016
DOI:10.1126/science.aad8279
Abstract
The ability to synthesize a diverse spectrum of one-dimensional (1D) nanocrystals presents an enticing prospect for exploring nanoscale size- and shape-dependent properties. Here we report a general strategy to craft a variety of plain nanorods, core-shell nanorods, and nanotubes with precisely controlled dimensions and compositions by capitalizing on functional bottlebrush-like block copolymers with well-defined structures and narrow molecular weight distributions as nanoreactors. These cylindrical unimolecular nanoreactors enable a high degree of control over the size, shape, architecture, surface chemistry, and properties of 1D nanocrystals. We demonstrate the synthesis of metallic, ferroelectric, upconversion, semiconducting, and thermoelectric 1D nanocrystals, among others, as well as combinations thereof.
Co-reporter:Chao Wang, Shuan Wang, Linkai Tang, Yan-Bing He, Lin Gan, Jia Li, Hongda Du, Baohua Li, Zhiqun Lin, Feiyu Kang
Nano Energy 2016 Volume 21() pp:133-144
Publication Date(Web):March 2016
DOI:10.1016/j.nanoen.2016.01.005
•Monodisperse Li4Ti5O12(LTO) nanospheres are crafted using TiN by the pH regulation.•Alkali environment effectively controls the formation of TiO2/Li+ nanospheres.•LTO can maintain the nanospheres by polyvinyl pyrrolidone coating layer.•The LTO nanospheres show high taping density and excellent performance.The ability to synthesizing monodisperse Li4Ti5O12 (LTO) nanospheres is the key to reducing the irreversible capacity of LTO materials, and thus improving their power performance. However, it remains a grand challenge to achieve uniform precursors of LTO nanospheres and maintain their spherical structures after annealing. Herein, we develop a robust strategy for the synthesis of monodisperse LTO nanospheres with an average diameter of 120 nm via the use of titanium nitride (TiN) as a titanium source for lithium ion batteries (LIBs). The precursors composed of uniform TiO2/Li+ nanospheres were formed in a stable alkaline environment during the course of heating of the solution of peroxo-titanium complex as a result of the dissolution of TiN, while TiO2/Li+ microspheres were easily yielded with the decrease in pH value of the precursor solution. The OH− anion was found to effectively retard the hydrolysis of peroxo-titanium complex as well as the aggregation of TiO2/Li+ nanoparticles. Intriguingly, a uniform polyvinyl pyrrolidone (PVP) layer formed in-situ on the surface of TiO2/Li+ nanospheres rendered LTO to retain the monodisperse spherical morphology after annealing. Notably, the as-prepared monodisperse LTO nanospheres comprised of the interconnected LTO nanograins with an average size of ~15 nm uniformly coated by a carbon layer derived from the carbonization of PVP exhibited a high tap density (1.1 g cm−3) and an outstanding rate-cycling capability. The charge specific capacities at 1, 10, 50 and 80 C were 159.5, 151.1, 128.8 and 108.9 mAh g−1, respectively. More importantly, the capacity retention after 500 cycles at 10 C was as high as 92.6%. This work opens up an avenue to craft the uniform precursors of LTO and thus monodisperse LTO nanospheres that possess superior rate performance with high volumetric energy densities and long-term cyclic stability.
Co-reporter:Dr. Ming He;Dr. Xinchang Pang;Xueqin Liu;Beibei Jiang;Yanjie He; Henry Snaith; Zhiqun Lin
Angewandte Chemie International Edition 2016 Volume 55( Issue 13) pp:4280-4284
Publication Date(Web):
DOI:10.1002/anie.201600702
Abstract
Extending the spectral absorption of organolead halide perovskite solar cells from visible into near-infrared (NIR) range renders the minimization of non-absorption loss of solar photons with improved energy alignment. Herein, we report on, for the first time, a viable strategy of capitalizing on judiciously synthesized monodisperse NaYF4:Yb/Er upconversion nanoparticles (UCNPs) as the mesoporous electrode for CH3NH3PbI3 perovskite solar cells and more importantly confer perovskite solar cells to be operative under NIR light. Uniform NaYF4:Yb/Er UCNPs are first crafted by employing rationally designed double hydrophilic star-like poly(acrylic acid)-block-poly(ethylene oxide) (PAA-b-PEO) diblock copolymer as nanoreactor, imparting the solubility of UCNPs and the tunability of film porosity during the manufacturing process. The subsequent incorporation of NaYF4:Yb/Er UCNPs as the mesoporous electrode led to a high efficiency of 17.8 %, which was further increased to 18.1 % upon NIR irradiation. The in situ integration of upconversion materials as functional components of perovskite solar cells offers the expanded flexibility for engineering the device architecture and broadening the solar spectral use.
Co-reporter:Dr. Ming He;Dr. Xinchang Pang;Xueqin Liu;Beibei Jiang;Yanjie He; Henry Snaith; Zhiqun Lin
Angewandte Chemie International Edition 2016 Volume 55( Issue 13) pp:
Publication Date(Web):
DOI:10.1002/anie.201601639
Co-reporter:Dr. Jaehan Jung;Chun Hao Lin;Young Jun Yoon;Sidney T. Malak;Yaxin Zhai; Edwin L. Thomas; Valy Vardeny; Vladimir V. Tsukruk; Zhiqun Lin
Angewandte Chemie International Edition 2016 Volume 55( Issue 16) pp:5071-5075
Publication Date(Web):
DOI:10.1002/anie.201601198
Abstract
The key to utilizing quantum dots (QDs) as lasing media is to effectively reduce non-radiative processes, such as Auger recombination and surface trapping. A robust strategy to craft a set of CdSe/Cd1−xZnxSe1−ySy/ZnS core/graded shell–shell QDs with suppressed re-absorption, reduced Auger recombination rate, and tunable Stokes shift is presented. In sharp contrast to conventional CdSe/ZnS QDs, which have a large energy level mismatch between CdSe and ZnS and thus show strong re-absorption and a constrained Stokes shift, the as-synthesized CdSe/Cd1−xZnxSe1−ySy/ZnS QDs exhibited the suppressed re-absorption of CdSe core and tunable Stokes shift as a direct consequence of the delocalization of the electron wavefunction over the entire QD. Such Stokes shift-engineered QDs with suppressed re-absorption may represent an important class of building blocks for use in lasers, light emitting diodes, solar concentrators, and parity-time symmetry materials and devices.
Co-reporter:Dr. Ming He;Dr. Xinchang Pang;Xueqin Liu;Beibei Jiang;Yanjie He; Henry Snaith; Zhiqun Lin
Angewandte Chemie 2016 Volume 128( Issue 13) pp:4352-4356
Publication Date(Web):
DOI:10.1002/ange.201600702
Abstract
Extending the spectral absorption of organolead halide perovskite solar cells from visible into near-infrared (NIR) range renders the minimization of non-absorption loss of solar photons with improved energy alignment. Herein, we report on, for the first time, a viable strategy of capitalizing on judiciously synthesized monodisperse NaYF4:Yb/Er upconversion nanoparticles (UCNPs) as the mesoporous electrode for CH3NH3PbI3 perovskite solar cells and more importantly confer perovskite solar cells to be operative under NIR light. Uniform NaYF4:Yb/Er UCNPs are first crafted by employing rationally designed double hydrophilic star-like poly(acrylic acid)-block-poly(ethylene oxide) (PAA-b-PEO) diblock copolymer as nanoreactor, imparting the solubility of UCNPs and the tunability of film porosity during the manufacturing process. The subsequent incorporation of NaYF4:Yb/Er UCNPs as the mesoporous electrode led to a high efficiency of 17.8 %, which was further increased to 18.1 % upon NIR irradiation. The in situ integration of upconversion materials as functional components of perovskite solar cells offers the expanded flexibility for engineering the device architecture and broadening the solar spectral use.
Co-reporter:Dr. Ming He;Dr. Xinchang Pang;Xueqin Liu;Beibei Jiang;Yanjie He; Henry Snaith; Zhiqun Lin
Angewandte Chemie 2016 Volume 128( Issue 13) pp:
Publication Date(Web):
DOI:10.1002/ange.201601639
Co-reporter:Dr. Jaehan Jung;Chun Hao Lin;Young Jun Yoon;Sidney T. Malak;Yaxin Zhai; Edwin L. Thomas; Valy Vardeny; Vladimir V. Tsukruk; Zhiqun Lin
Angewandte Chemie 2016 Volume 128( Issue 16) pp:5155-5159
Publication Date(Web):
DOI:10.1002/ange.201601198
Abstract
The key to utilizing quantum dots (QDs) as lasing media is to effectively reduce non-radiative processes, such as Auger recombination and surface trapping. A robust strategy to craft a set of CdSe/Cd1−xZnxSe1−ySy/ZnS core/graded shell–shell QDs with suppressed re-absorption, reduced Auger recombination rate, and tunable Stokes shift is presented. In sharp contrast to conventional CdSe/ZnS QDs, which have a large energy level mismatch between CdSe and ZnS and thus show strong re-absorption and a constrained Stokes shift, the as-synthesized CdSe/Cd1−xZnxSe1−ySy/ZnS QDs exhibited the suppressed re-absorption of CdSe core and tunable Stokes shift as a direct consequence of the delocalization of the electron wavefunction over the entire QD. Such Stokes shift-engineered QDs with suppressed re-absorption may represent an important class of building blocks for use in lasers, light emitting diodes, solar concentrators, and parity-time symmetry materials and devices.
Co-reporter:Yingkui Yang;Wenjie Zhan;Rengui Peng;Chengen He;Xinchang Pang;Dean Shi;Tao Jiang
Advanced Materials 2015 Volume 27( Issue 41) pp:6376-6381
Publication Date(Web):
DOI:10.1002/adma.201503680
Co-reporter:Meidan Ye, Xiaoru Wen, Mengye Wang, James Iocozzia, Nan Zhang, Changjian Lin, Zhiqun Lin
Materials Today 2015 Volume 18(Issue 3) pp:155-162
Publication Date(Web):April 2015
DOI:10.1016/j.mattod.2014.09.001
Dye-sensitized solar cells (DSSCs), as low-cost photovoltaic devices compared to conventional silicon solar cells, have received widespread attention in recent years; although much work is required to reach optimal device efficiencies. This review highlights recent developments in DSSCs and their key components, including the photoanode, sensitizer, electrolyte and counter electrode.
Co-reporter:Songping Wu;Rui Xu;Mingjia Lu;Rongyun Ge;James Iocozzia;Cuiping Han;Beibei Jiang
Advanced Energy Materials 2015 Volume 5( Issue 21) pp:
Publication Date(Web):
DOI:10.1002/aenm.201500400
Graphene-containing nanomaterials have emerged as important candidates for electrode materials in lithium-ion batteries (LIBs) due to their unique physical properties. In this review, a brief introduction to recent developments in graphene-containing nanocomposite electrodes and their derivatives is provided. Subsequently, synthetic routes to nanoparticle/graphene composites and their electrochemical performance in LIBs are highlighted, and the current state-of-the-art and most recent advances in the area of graphene-containing nanocomposite electrode materials are summarized. The limitations of graphene-containing materials for energy storage applications are also discussed, with an emphasis on anode and cathode materials. Potential research directions for the future development of graphene-containing nanocomposites are also presented, with an emphasis placed on practicality and scale-up considerations for taking such materials from benchtop curiosities to commercial products.
Co-reporter:Seok Hee Kang, Wan Sik Hwang, Zhiqun Lin, Se Hun Kwon, and Suck Won Hong
Nano Letters 2015 Volume 15(Issue 12) pp:7913-7920
Publication Date(Web):November 16, 2015
DOI:10.1021/acs.nanolett.5b02946
Because of its excellent charge carrier mobility at the Dirac point, graphene possesses exceptional properties for high-performance devices. Of particular interest is the potential use of graphene nanoribbons or graphene nanomesh for field-effect transistors. Herein, highly aligned DNA nanowire arrays were crafted by flow-assisted self-assembly of a drop of DNA aqueous solution on a flat polymer substrate. Subsequently, they were exploited as “ink” and transfer-printed on chemical vapor deposited (CVD)-grown graphene substrate. The oriented DNA nanowires served as the lithographic resist for selective removal of graphene, forming highly aligned graphene nanoribbons. Intriguingly, these graphene nanoribbons can be readily produced over a large area (i.e., millimeter scale) with a high degree of feature-size controllability and a low level of defects, rendering the fabrication of flexible two terminal devices and field-effect transistors.
Co-reporter:Beibei Jiang; Xinchang Pang; Bo Li
Journal of the American Chemical Society 2015 Volume 137(Issue 36) pp:11760-11767
Publication Date(Web):August 27, 2015
DOI:10.1021/jacs.5b06736
Organic–inorganic nanocomposites composed of polymers and nanoparticles offer a vast design space of potential material properties, depending heavily on the properties of these two constituents and their spatial arrangement. The ability to place polymers in direct contact with functional nanoparticles via strong bonding, that is, stable chemical interaction without the dissociation of surface capping polymers, provides a means of preventing nanoparticles from aggregation and increasing their dispersibility in nanocomposites, and promises opportunities to explore new properties and construction of miniaturized devices. However, this is still a challenging issue and has not yet been largely explored. Here, we report an unconventional strategy to create in situ organic–inorganic nanocomposites comprising monodisperse ferroelectric nanoparticles directly and permanently tethered with ferroelectric polymers by capitalizing on rationally designed amphiphilic star-like diblock copolymer as nanoreactors. The diameter of ferroelectric nanoparticles and the chain length of ferroelectric polymers can be precisely tuned. The dielectric and ferroelectric properties of nanocomposites containing different sizes of ferroelectric nanoparticles were scrutinized. Such bottom-up crafting of intimate organic–inorganic nanocomposites offers new levels of tailorability to nanostructured materials and promises new opportunities for achieving exquisite control over the surface chemistry and properties of nanocomposites with engineered functionality for diverse applications in energy conversion and storage, catalysis, electronics, nanotechnology, and biotechnology.
Co-reporter:Jianqiang Hu; Aili Liu; Huile Jin; Dekun Ma; Dewu Yin; Pengsheng Ling; Shun Wang; Zhiqun Lin;Jichang Wang
Journal of the American Chemical Society 2015 Volume 137(Issue 34) pp:11004-11010
Publication Date(Web):August 13, 2015
DOI:10.1021/jacs.5b04784
A series of multi-heterostructured metal chalcogenides (CdS-Te, NiS/CdS-Te, and MoS2/CdS-Te) with a surprising shish-kebab-like structure have been synthesized via a one-step microwave-assisted pyrolysis of dithiocarbamate precursors in ethylene glycol. Subsequently, CdS-Te composites were exploited as a self-sacrificial template to craft various CdS-Te@(Pt, Pd) multi-heterostructures. Highly uniform dispersion and intimate interactions between CdS and multicomponent cocatalysts, together with improved separation of photogenerated carriers due to the presence of Te nanotubes (NTs) and trace CdTe, enable CdS-based heterostructured photocatalysts to exhibit greatly enhanced efficiency and stability in the photocatalytic production of H2. Thorough morphological characterizations revealed that the growth of metal sulfide/Te heterostructures originates from the growth of Te tubes, which is likely governed by diffusion-limited depletion of the Te precursor and the dissolution–crystallization process of Te seeds followed by the formation of metal sulfide kebabs.
Co-reporter:Bo Li, Beibei Jiang, Haillong Tang and Zhiqun Lin
Chemical Science 2015 vol. 6(Issue 11) pp:6349-6354
Publication Date(Web):20 Jul 2015
DOI:10.1039/C5SC02337H
Ultrathin Au nanowires have garnered increasing attention in recent years because of their potential use in a range of applications due to their unique optical properties, conductivity, chemical activity, and discrete plasticity. Herein, we report an unconventional seed-mediated growth of ultrathin Au nanowires induced by hydrophobic molecules. Quite intriguingly, by adding a trace amount of hydrophobic molecules (i.e., toluene or chloroform) to the Au growth solution conventionally used for the growth of Au nanorods with cylindrical CTAB micelles as templates, CTAB-capped ultrathin Au nanowires (i.e., water-soluble ultrathin Au nanowires) were crafted. Similarly to the growth of Au nanorods, silver ions and Au seeds were crucially required to yield the water-soluble ultrathin Au nanowires. The growth mechanism of these ultrathin nanowires was also explored.
Co-reporter:Dajiang Zheng, Xinchang Pang, Mengye Wang, Yanjie He, Changjian Lin, and Zhiqun Lin
Chemistry of Materials 2015 Volume 27(Issue 15) pp:5271
Publication Date(Web):July 21, 2015
DOI:10.1021/acs.chemmater.5b01422
Atom transfer radical polymerization (ATRP) of 4-vinylpyridine, t-butyl acrylate, and styrene in sequential order from a β-cyclodextrin core yielded an amphiphilic star-like triblock copolymer, poly(4-vinylpyridine)-block-poly(t-butyl acrylate)-block-polystyrene (P4VP-b-PtBA-b-PS). Subsequently, star-like triblock copolymer composed of inner hydrophilic P4VP blocks, central hydrophobic PtBA blocks, and outer hydrophobic PS blocks with well-defined molecular architecture and molecular weight of each block was judiciously exploited as nanoreactor for synthesis of precisely shaped hairy plasmonic/semiconductor Au/TiO2 core/shell nanoparticles. The resulting Au/TiO2 nanoparticles were intimately and permanently tethered with outer PS chains that enabled the superior solubility of nanoparticles in nonpolar solvents. The PS chains on the surface of these bifunctional nanoparticles were carbonized by annealing in an inert atmosphere (i.e., yielding carbon-coated Au/TiO2 nanoparticles). In comparison to a widely used TiO2 network film (i.e., P25)-based device, dye-sensitized solar cells assembled by incorporating a thin layer of carbonized Au/TiO2 nanoparticles on the top of P25 film as photoanode exhibited largely improved short-circuit current density, JSC (18.4% increase), and power conversion efficiency, PCE (13.6% increase), respectively. Such improvements were attributed to the surface plasmon-enabled light harvesting enhancement of Au core and fast electron transport promoted by the carbon layer coating on Au/TiO2 nanoparticles, as revealed by external quantum efficiency (EQE), UV–vis spectroscopy, and electrochemical impedance spectroscopy measurements, respectively.
Co-reporter:Hailong Tang, Yanjie He, Bo Li, Jaehan Jung, Chuchu Zhang, Xiaobo Liu and Zhiqun Lin
Nanoscale 2015 vol. 7(Issue 21) pp:9731-9737
Publication Date(Web):27 Apr 2015
DOI:10.1039/C5NR01492A
Recent research has witnessed rapid advances in synthesis of nanocrystals, which has led to the development of a large variety of approaches for producing nanocrystals with controlled dimensions. However, most of these techniques lack the high-throughput production. Herein, we report on a viable and robust strategy based on an inert-gas-driven microflow reactor for continuous crafting of high-quality colloidal nanocrystals. With the judicious introduction of the inert-gas driven capability, the microflow reactor provides an attractive platform for continuous production of colloidal nanocrystals in large quantities, including easily-oxidized nanocrystals. The as-synthesized nanocrystals possessed a uniform size and shape. Intriguingly, the size of nanocrystals can be effectively tailored by varying the flow rate and the precursor concentration. We envision that the microflow reactor strategy is general and offers easy access to a wide range of scalable nanocrystals for potential applications in sensors, optics, optoelectronics, solar energy conversion, batteries, photocatalysis, and electronic devices.
Co-reporter:Di Yang, Mengye Wang, Bin Zou, Gu Ling Zhang and Zhiqun Lin
Nanoscale 2015 vol. 7(Issue 30) pp:12990-12997
Publication Date(Web):30 Jun 2015
DOI:10.1039/C5NR02685G
Solid amorphous TiO2 mesospheres were synthesized by controlled hydrolysis of Ti-containing precursors. Subsequently, solid TiO2 mesospheres were exploited as scaffolds and subjected to a one-step external template-free hydrothermal treatment, yielding intriguing hollow anatase TiO2 mesospheres. The synthetic protocol was optimized by investigating the effect of buffer reagents and fluoride ions on the formation of hollow TiO2 spheres. The diameter of hollow mesospheres, ranging from 308 to 760 nm, can be readily tailored by varying the precursor concentration. The average thickness of a shell composed of TiO2 nanocrystals was approximately 40 nm with a mean crystal size of 12.4–20.0 nm. Such hollow TiO2 mesospheres possessed a large surface area and were employed in photocatalytic degradation of methylene blue under UV irradiation. Interestingly, the synthetic conditions were found to exert a significant influence on the photocatalytic ability of hollow TiO2 mesospheres. The correlation between the degradation ability of hollow TiO2 mesospheres and the precursor concentration as well as the hydrothermal time was scrutinized. The optimal photocatalytic performance of hollow TiO2 mesospheres was identified.
Co-reporter:Wenming Liao, Dajiang Zheng, Jianhua Tian and Zhiqun Lin
Journal of Materials Chemistry A 2015 vol. 3(Issue 46) pp:23360-23367
Publication Date(Web):05 Oct 2015
DOI:10.1039/C5TA06238A
Upconversion/semiconductor submicron hollow spheres composed of inner NaxGdFyOz:Yb/Er shell and outer TiO2 shell (denoted NaxGdFyOz:Yb/Er@TiO2) were, for the first time, crafted by exploiting colloidal carbon spheres as the scaffold. The hollow spheres were then incorporated into the TiO2 nanoparticle film photoanode to yield dye-sensitized solar cells (DSSCs) with improved performance. The implementation of NaxGdFyOz:Yb/Er@TiO2 hollow spheres in DSSCs imparted the light trapping due to the light scattering from submicron hollow spheres, and the harvesting of near infrared solar photons by the upconversion material (i.e., dual functionalities), thereby resulting in an increased short-circuit current density Jsc, and thus an improved power conversion efficiency PCE. The electrochemical impedance spectroscopy measurements were performed to scrutinize the interfacial charge transfer characteristics of DSSCs. The measurements revealed that when NaxGdFyOz:Yb/Er hollow spheres without the deposition of TiO2 shell were integrated in the photoanode, a high charge transfer resistance was found. In stark contrast, the judicious decoration of NaxGdFyOz:Yb/Er hollow spheres with a thin layer of TiO2 shell markedly improved the contact between the resulting NaxGdFyOz:Yb/Er@TiO2 shell/shell hollow spheres and the TiO2 nanoparticle film photoanode, leading to a much decreased charge transfer resistance. Taken together, compared to the PCE of 6.81% for the pristine device, the DSSC assembled with the introduction of 8 wt% NaxGdFyOz:Yb/Er@TiO2 hollow spheres in the photoanode exhibited an optimal PCE of 7.58% and a maximum short-circuit current density Jsc of 18.72 mA cm−2 under AM 1.5G one sun illumination, corresponding to 11.31% performance enhancement. As such, the implementation of upconversion submicron hollow materials in photoanode may stand out as an intriguing strategy to improve the device performance of DSSCs.
Co-reporter:Xueqin Liu, Zhen Li, Wen Zhao, Caixin Zhao, Yang Wang and Zhiqun Lin
Journal of Materials Chemistry A 2015 vol. 3(Issue 37) pp:19148-19154
Publication Date(Web):12 Aug 2015
DOI:10.1039/C5TA05508C
Reduced graphene oxide (rGO)-wrapped octahedral Cu2O composites (GCCs) were successfully produced by an ultrasonication-assisted reduction of graphene oxide (GO) in the Cu2O precursor solution. During the ultrasound reaction, the reduction of GO and the growth of octahedral Cu2O crystals occurred simultaneously in conjunction with the deposition of Cu2O crystals on graphene. As a result of the introduction of rGO, the light absorption of octahedral Cu2O was markedly improved, the size of Cu2O crystals was decreased, and the self-aggregation of Cu2O crystals was effectively prevented. More importantly, the charge separation and transfer were effectively enhanced. Compared to the pure octahedral Cu2O crystals and commercial TiO2 (P25), the GCCs exhibited an increased degradation rate of methyl orange (MO) by 4.5 and 20.2 times, respectively. Meanwhile, upon the graphene loading, the photoelectric conversion efficiency of GCC electrodes was largely improved resulting in an efficiency of 0.151%, representing an 8 fold higher efficiency than that of pure Cu2O crystals.
Co-reporter:Xiong Zhang, Yuekun Lai, Mingzheng Ge, Yaxin Zheng, Ke-Qin Zhang and Zhiqun Lin
Journal of Materials Chemistry A 2015 vol. 3(Issue 25) pp:13577-13577
Publication Date(Web):04 Jun 2015
DOI:10.1039/C5TA90128F
Correction for ‘Fibrous and flexible supercapacitors comprising hierarchical nanostructures with carbon spheres and graphene oxide nanosheets’ by Xiong Zhang et al., J. Mater. Chem. A, 2015, DOI: 10.1039/c5ta03252k.
Co-reporter:Cuiping Han, Di Yang, Yingkui Yang, Beibei Jiang, Yanjie He, Mengye Wang, Ah-Young Song, Yan-Bing He, Baohua Li and Zhiqun Lin
Journal of Materials Chemistry A 2015 vol. 3(Issue 25) pp:13340-13349
Publication Date(Web):15 May 2015
DOI:10.1039/C5TA02070K
By subjecting amorphous titanium dioxide (TiO2) colloidal spheres as a scaffold to a two-step external template-free hydrothermal treatment, anatase TiO2 hollow spheres with an average diameter of 410 nm and shell thickness of 65 nm were successfully yielded. Such hollow TiO2 nanostructures possessed a large surface area, abundant active sites and reduced Li ion diffusion path and thus were highly favorable for use in TiO2-based lithium ion batteries (LIB). Electrochemical measurements revealed that as-prepared TiO2 hollow spheres exhibited specific discharge capacities of 296, 185, 118, 66 and 37 mA h g−1 at 0.1 C, 1 C, 2 C, 5 C and 10 C, respectively. This is in sharp contrast to the considerably lower values obtained in TiO2 solid nanoparticles (i.e., 182, 119, 81, 43 18 mA h g−1 at discharge rates of 0.1 C, 1 C, 2 C, 5 C and 1 0 C, respectively). Interestingly, TiO2 hollow spheres showed a large irreversible capacity loss and relatively low cycling performance due to the residual chemisorbed water in TiO2 and hydroxyl groups present on the TiO2 surface. A solid electrolyte interface (SEI) layer composed primarily of Li2CO3, lithium alkyl carbonates and organic phosphates was thus formed on the surface of hollow TiO2 spheres, thereby leading to an increased internal cell impedance and the decreased rate and cycling performance. The subsequent high-temperature annealing effectively removed chemisorbed water and hydroxyls on the TiO2 surface. As a consequence, annealed TiO2 hollow spheres rendered markedly improved rate stability and cycle performance in the resulting TiO2-based LIBs. The specific discharge capacities at rates of 5 C and 10 C were 77 mA h g−1 and 50 mA h g−1, which are considerably larger than those obtained from as-prepared TiO2 hollow spheres. Moreover, compared to only 42.1% for as-prepared hollow TiO2 spheres, a capacity retention as high as 93.5% over 200 cycles at 1 C was achieved for annealed hollow TiO2 spheres.
Co-reporter:Xiong Zhang, Yuekun Lai, Mingzheng Ge, Yaxin Zheng, Ke-Qin Zhang and Zhiqun Lin
Journal of Materials Chemistry A 2015 vol. 3(Issue 24) pp:12761-12768
Publication Date(Web):07 May 2015
DOI:10.1039/C5TA03252K
A fibrous, flexible supercapacitor (FFSC) electrode with unique layer-by-layer structures is constructed using a one-step electrophoretic method. The highly enhanced capacitance of 53.56 mF cm−2 and good charge/discharge stability is attributed to the synergistic effect between the GO nano-sheet and carbon nano-sphere for electrolyte contact and ion transportation. Such a construction method can be employed to construct various FFSC electrodes for portable energy storage and wearable electronics applications.
Co-reporter:Songping Wu, Yichao Lv, Mingjia Lu and Zhiqun Lin
Journal of Materials Chemistry A 2015 vol. 3(Issue 13) pp:3121-3127
Publication Date(Web):11 Feb 2015
DOI:10.1039/C4TC02828G
Multiferroic ErMn2O5 nanorods have been synthesized via a surfactant-templated hydrothermal route. An environmentally friendly natural surfactant (Arabic gum) has been utilized as a template to prepare ErMn2O5 nanorods with a controllable morphology and size (i.e., nanorods with various lengths and basically invariable diameter). ErMn2O5 nanorods show strong size-dependent magnetic properties that correlate with: (a) a critical length for magnetization, and (b) recognizable divagation between FC and ZFC curves at low temperature. The former could be ascribed to the competition between surface strain and uncompensated spin at the surface, and the latter to Er antiferromagnetic ordering.
Co-reporter:Chaowei Feng, Xinchang Pang, Yanjie He, Yihuang Chen, Guangzhao Zhang and Zhiqun Lin
Polymer Chemistry 2015 vol. 6(Issue 29) pp:5190-5197
Publication Date(Web):09 Jun 2015
DOI:10.1039/C5PY00765H
A viable strategy for uniform organo-silica hybrid nanoparticles and nanocapsules was developed. The key to our strategy is the implementation of spherical star-like homopolymers and diblock copolymers with well-controlled molecular weights that form unimolecular micelles in solution as nanoreactors. Organo-silica hybrid nanoparticles were crafted by introducing trimethoxysilyl functionalities to the arm of star-like homopolymers. Quite intriguingly, organo-silica hybrid nanocapsules with an interior cavity were created when the trimethoxysilyl moieties were incorporated into the outer block of star-like diblock copolymers. The diameter of hybrid nanoparticles and the shell thickness of hybrid nanocapsules can be readily tailored via the living polymerization of star-like homopolymer and diblock copolymer nanoreactors, respectively. These hybrid nanoparticles and nanocapsules may find promising applications in polymer nanocomposites, water purification, separation, catalysis, and drug delivery. We envision that the nanoreactor strategy is general and robust. By rationally designing nonlinear yet structurally regular polymers possessing metal-containing units, other exotic metal- and metal oxide-containing nanostructures can also be easily accessed for a variety of applications.
Co-reporter:Hui Xu;Yuci Xu;Xinchang Pang;Jaehan Jung;Haiping Xia;Yanjie He
Science Advances 2015 Volume 1(Issue 2) pp:e1500025
Publication Date(Web):27 Mar 2015
DOI:10.1126/sciadv.1500025
Organic-inorganic 1D periodic necklace-like nanostructures are fabricated using confined synthesis of inorganic nanocrystals.
Co-reporter: Di Yang;Xinchang Pang;Yanjie He; Yiquan Wang;Genxiang Chen;Wenzhong Wang; Zhiqun Lin
Angewandte Chemie 2015 Volume 127( Issue 41) pp:12259-12264
Publication Date(Web):
DOI:10.1002/ange.201504676
Abstract
Star-like amphiphilic triblock copolymers were rationally designed and synthesized by combining two sequential atom-transfer radical polymerization reactions with a click reaction. Subsequently, a family of uniform magnetic/plasmonic core/shell nanoparticles was crafted by capitalizing on these triblock copolymers as nanoreactors. The diameter of the magnetic core and the thickness of the plasmonic shell could be independently and accurately controlled by varying the molecular weights (i.e., the chain lengths) of the inner and intermediate blocks of the star-like triblock copolymers, respectively. The surface plasmonic absorption of core/shell nanoparticles with different core diameters and shell thicknesses was systematically studied and theoretically modeled. This robust strategy provides easy access to a large variety of multifunctional nanoparticles with large lattice mismatches for use in optics, optoelectronics, catalysis, or bioimaging.
Co-reporter:Bo Li;Chuchu Zhang;Beibei Jiang;Dr. Wei Han ; Zhiqun Lin
Angewandte Chemie International Edition 2015 Volume 54( Issue 14) pp:4250-4254
Publication Date(Web):
DOI:10.1002/anie.201412388
Abstract
One-dimensional nanowires enable the realization of optical and electronic nanodevices that may find applications in energy conversion and storage systems. Herein, large-scale aligned DNA nanowires were crafted by flow-enabled self-assembly (FESA). The highly oriented and continuous DNA nanowires were then capitalized on either as a template to form metallic nanowires by exposing DNA nanowires that had been preloaded with metal salts to an oxygen plasma or as a scaffold to direct the positioning and alignment of metal nanoparticles and nanorods. The FESA strategy is simple and easy to implement and thus a promising new method for the low-cost synthesis of large-scale one-dimensional nanostructures for nanodevices.
Co-reporter: Di Yang;Xinchang Pang;Yanjie He; Yiquan Wang;Genxiang Chen;Wenzhong Wang; Zhiqun Lin
Angewandte Chemie International Edition 2015 Volume 54( Issue 41) pp:12091-12096
Publication Date(Web):
DOI:10.1002/anie.201504676
Abstract
Star-like amphiphilic triblock copolymers were rationally designed and synthesized by combining two sequential atom-transfer radical polymerization reactions with a click reaction. Subsequently, a family of uniform magnetic/plasmonic core/shell nanoparticles was crafted by capitalizing on these triblock copolymers as nanoreactors. The diameter of the magnetic core and the thickness of the plasmonic shell could be independently and accurately controlled by varying the molecular weights (i.e., the chain lengths) of the inner and intermediate blocks of the star-like triblock copolymers, respectively. The surface plasmonic absorption of core/shell nanoparticles with different core diameters and shell thicknesses was systematically studied and theoretically modeled. This robust strategy provides easy access to a large variety of multifunctional nanoparticles with large lattice mismatches for use in optics, optoelectronics, catalysis, or bioimaging.
Co-reporter:Bo Li;Chuchu Zhang;Beibei Jiang;Dr. Wei Han ; Zhiqun Lin
Angewandte Chemie 2015 Volume 127( Issue 14) pp:4324-4328
Publication Date(Web):
DOI:10.1002/ange.201412388
Abstract
One-dimensional nanowires enable the realization of optical and electronic nanodevices that may find applications in energy conversion and storage systems. Herein, large-scale aligned DNA nanowires were crafted by flow-enabled self-assembly (FESA). The highly oriented and continuous DNA nanowires were then capitalized on either as a template to form metallic nanowires by exposing DNA nanowires that had been preloaded with metal salts to an oxygen plasma or as a scaffold to direct the positioning and alignment of metal nanoparticles and nanorods. The FESA strategy is simple and easy to implement and thus a promising new method for the low-cost synthesis of large-scale one-dimensional nanostructures for nanodevices.
Co-reporter:Mengye Wang, James Ioccozia, Lan Sun, Changjian Lin and Zhiqun Lin
Energy & Environmental Science 2014 vol. 7(Issue 7) pp:2182-2202
Publication Date(Web):14 Apr 2014
DOI:10.1039/C4EE00147H
Semiconductor photocatalysis is a promising physicochemical process for the photodegradation of organic contaminants and bacterial detoxification. Among various oxide semiconductor photocatalysts, TiO2 has garnered considerable attention because of its outstanding properties including strong oxidizing activity, chemical and mechanical stability, corrosion resistance, and nontoxicity. This Review briefly introduces the key mechanisms of photocatalysis, highlights the recent developments pertaining to pure TiO2 nanotube arrays and TiO2 nanotube arrays modified by non-metals, metals and semiconductors, and their applications in the photocatalytic degradation of organic dyes. The improved photocatalytic efficiencies of modified TiO2 nanotube arrays are compared with unmodified counterparts. Current challenges and prospective areas of interest in this rich field are also presented.
Co-reporter:Xiao-Yu Cao, Qianyi Zhao, Zhiqun Lin, and Haiping Xia
Accounts of Chemical Research 2014 Volume 47(Issue 2) pp:341
Publication Date(Web):November 14, 2013
DOI:10.1021/ar400087x
Aromatic compounds, such as benzene and its derivatives, porphyrins, fullerenes, carbon nanotubes, and graphene, have numerous applications in biomedicine, materials science, energy science, and environmental science. Metalla-aromatics are analogues of conventional organic aromatic molecules in which one of the (hydro)carbon segments is formally replaced by an isolobal transition-metal fragment. Researchers have studied these transition-metal-containing aromatic molecules for the past three decades, particularly the synthesis and reactivity of metallabenzenes. Another focus has been the preparation and characterization of other metalla-aromatics such as metallafurans, metallapyridines, metallabenzynes, and more. Despite significant advances, remaining challenges in this field include the limited number of convenient and versatile synthetic methods to construct stable and fully characterized metalla-aromatics, and the relative shortage of new topologies.To address these challenges, we have developed new methods for preparing metalla-aromatics, especially those possessing new topologies. Our synthetic efforts have led to a large family of closely related metalla-aromatics known as aromatic osmacycles. This Account summarizes the synthesis and reactivity of these compounds, with a focus on features that are different from those of compounds developed by other groups. These osmacycles can be synthesized from simple precursors under mild conditions. Using these efficient methods, we have synthesized aromatic osmacycles such as osmabenzene, osmabenzyne, isoosmabenzene, osmafuran, and osmanaphthalene. Furthermore, these methods have also created a series of new topologies, such as osmabenzothiazole and osmapyridyne. Our studies of the reactivity of these osma-aromatics revealed unprecedented reaction patterns, and we demonstrated the interconversion of several osmacycles.Like other metalla-aromatics, osma-aromatics have spectroscopic features of aromaticity, such as ring planarity and the characteristic bond lengths between a single and double bond, but the osma-aromatics we have prepared also exhibit good stability towards air, water, and heat. Indeed, some seemingly unstable species proved stable, and their stability made it possible to study their optical, electrochemical, and magnetic properties. The stability of these compouds results from their aromaticity and the phosphonium substituents on the aromatic plane: most of our osma-aromatics carry at least one phosphonium group. The phosphonium group offers stability via both electronic and steric mechanisms. The phosphonium acts as an electron reservoir, allowing the circulation of electron pairs along metallacycles and lowering the electron density of the aromatic rings. Meanwhile, the bulky phosphonium groups surrounding the aromatic metallacycle prevent most reactions that could decompose the skeleton.
Co-reporter:Chaowei Feng, Xinchang Pang, Yanjie He, Bo Li, and Zhiqun Lin
Chemistry of Materials 2014 Volume 26(Issue 20) pp:6058
Publication Date(Web):September 29, 2014
DOI:10.1021/cm503108z
Unimolecular core–shell and hollow polymer nanoparticles with well-defined dimensions were crafted using spherical core–shell star-like diblock copolymers as templates. Monodisperse and structurally stable star-like diblock copolymers composed of inner degradable core blocks and outer photo-cross-linkable shell blocks were synthesized via a combination of two living polymerization techniques, namely, coordination–insertion ring opening polymerization (ROP) followed by reversible addition–fragmentation chain-transfer polymerization (RAFT). Subsequently, uniform unimolecular core–shell nanoparticles were successfully produced by photo-cross-linking the shell blocks of star-like diblock copolymers. The core diameter and shell thickness of nanoparticles are determined by molecular weights of inner core block and outer shell block, respectively, thereby rendering nanoparticles with tunable structural characteristics. The cross-linking density of nanoparticles can be readily controlled by varying the exposure time of star-like diblock copolymer templates to UV illumination. The selective degradation of inner core blocks yielded hollow polymer nanoparticles which retained structural integrity. The dye encapsulation and release studies revealed that unimolecular core–shell nanoparticles may be exploited as a new class of nanocarriers and promising drug nanovehicles.
Co-reporter:Ming He, Dajiang Zheng, Mengye Wang, Changjian Lin and Zhiqun Lin
Journal of Materials Chemistry A 2014 vol. 2(Issue 17) pp:5994-6003
Publication Date(Web):01 Nov 2013
DOI:10.1039/C3TA14160H
Perovskite solar cells have garnered great attention in recent years as promising high performance next-generation solar cells with long-term stability at low cost. Since the seminal work of Miyasaka and others in 2009, the power conversion efficiency (PCE) of perovskite-based dye-sensitized solar cells (DSSCs) has rapidly increased from 3.8% to 15% over the past four years, exceeding the highest efficiency of conventional organic dye-sensitized DSSCs. Recently, the perovskite has been demonstrated to act successfully as an active layer in simple planar-heterojunction solar cells with no need of complex nanostructured DSSC architectures, leading to an attractively high PCE of 15.4% at a competitive low manufacturing cost. In this Feature Article, we aim to review the recent impressive development in perovskite solar cells, and discuss the prognosis for future progress in exploiting perovskite materials for high efficiency solar cells.
Co-reporter:Songping Wu, Rui Wang, Zhuolin Wang and Zhiqun Lin
Nanoscale 2014 vol. 6(Issue 14) pp:8350-8358
Publication Date(Web):26 May 2014
DOI:10.1039/C4NR00921E
A facile one-step route was developed to synthesize crystalline CuGeO3 nanowire/graphene composites (CGCs). Crystalline CuGeO3 nanowires were tightly covered and anchored by graphene sheets, forming a layered structure. Subsequently, CGCs were exploited as electrode materials for lithium ion batteries (LIBs). The reversible formation of Li2O buffer layer and elastic graphene sheets accommodated the volume change during the charge and discharge processes. CGC containing 37 wt% graphene exhibited a superior electrochemical performance, that is, a remarkable reversible capacity (1265 mA h g−1 for the first cycle), an outstanding cyclic performance (853 mA h g−1 after 50 cycles under a current density of 200 mA g−1), a high coulombic efficiency, and an excellent rate capability. Clearly, CGCs may stand out as a promising anode material for LIBs.
Co-reporter:Ming He, Mengye Wang, Changjian Lin and Zhiqun Lin
Nanoscale 2014 vol. 6(Issue 8) pp:3984-3994
Publication Date(Web):02 Jan 2014
DOI:10.1039/C3NR06298H
Rational design and synthesis of low bandgap (LBG) polymers with judiciously tailored HOMO and LUMO levels have emerged as a viable route to high performance polymer solar cells with power conversion efficiencies (PCEs) exceeding 10%. In addition to engineering the energy-level of LBG polymers, the photovoltaic performance of LBG polymer-based solar cells also relies on the device architecture, in particular the fine morphology of the photoactive layer. The nanoscale interpenetrating networks composed of nanostructured donor and acceptor phases are the key to providing a large donor–acceptor interfacial area for maximizing the exciton dissociation and offering a continuous pathway for charge transport. In this Review Article, we summarize recent strategies for tuning the molecular organization and nanoscale morphology toward an enhanced photovoltaic performance of LBG polymer-based solar cells.
Co-reporter:Meidan Ye, Mengye Wang, Dajiang Zheng, Nan Zhang, Changjian Lin and Zhiqun Lin
Nanoscale 2014 vol. 6(Issue 7) pp:3576-3584
Publication Date(Web):20 Dec 2013
DOI:10.1039/C3NR05564G
By subjecting amorphous flower-like TiO2 to a facile hydrothermal synthesis in the presence of Sr2+, garden-like perovskite SrTiO3 superstructures were achieved. The amorphous TiO2 was preformed using ZnO flowers as templates. Different three-dimensional SrTiO3 architectures were coexisted in the garden, including SrTiO3 flowers composed of several hollow sword-shaped petals, many sheet-shaped petals or numerous flake-shaped petals, and SrTiO3 grass consisting of a number of long blades. These SrTiO3 superstructures were simultaneously grown on fluorine-doped tin oxide (FTO) substrates. On the basis of a comprehensive study on the effects of growth time, temperature, initial concentrations of precursor, and pH, the formation of these various hierarchical architectures was attributed primarily to the dissolution of amorphous TiO2 and precipitation of perovskite crystals, followed by the Ostwald ripening process of perovskite nanocrystals and self-organization of perovskite building blocks. Interestingly, this approach can be readily extended to create other perovskite structures, including dendritic BaTiO3 and nest-like CaTiO3, as well as PbTiO3 transformed from plate-like pyrochlore Pb2Ti2O6 after post-thermal treatment. Garden-like SrTiO3 superstructures showed a superior photocatalytic performance when compared to other as-prepared semiconductors and perovskite materials (i.e., ZnO, TiO2, BaTiO3, CaTiO3 and PbTiO3), probably due to their intrinsic photocatalytic activity and special garden-like features with a coexistence of various structures that significantly facilitated the adsorption and diffusion of methyl blue (MB) molecules and oxygen species in the photochemical reaction of MB degradation.
Co-reporter:Meidan Ye, Dajiang Zheng, Mengye Wang, Chang Chen, Wenming Liao, Changjian Lin, and Zhiqun Lin
ACS Applied Materials & Interfaces 2014 Volume 6(Issue 4) pp:2893
Publication Date(Web):January 27, 2014
DOI:10.1021/am405442n
Peachlike rutile TiO2 microsphere films were successfully produced on transparent conducting fluorine-doped tin oxide substrate via a facile, one-pot chemical bath route at low temperature (T = 80–85 °C) by introducing polyethylene glycol (PEG) as steric dispersant. The formation of TiO2 microspheres composed of nanoneedles was attributed to the acidic medium for the growth of 1D needle-shaped building blocks where the steric interaction of PEG reduced the aggregation of TiO2 nanoneedles and the Ostwald ripening process. Dye-sensitized solar cells (DSSCs) assembled by employing these complex rutile TiO2 microspheres as photoanodes exhibited a light-to-electricity conversion efficiency of 2.55%. It was further improved to a considerably high efficiency of 5.25% upon a series of post-treatments (i.e., calcination, TiCl4 treatment, and O2 plasma exposure) as a direct consequence of the well-crystallized TiO2 for fast electron transport, the enhanced capacity of dye loading, the effective light scattering, and trapping from microstructures.Keywords: chemical bath method; dye-sensitized solar cells; light-to-electricity conversion efficiency; low-temperature synthesis; post-treatments; rutile TiO2 microspheres;
Co-reporter:Hailong Tang, Zejun Pu, Xu Huang, Junji Wei, Xiaobo Liu and Zhiqun Lin
Polymer Chemistry 2014 vol. 5(Issue 11) pp:3673-3679
Publication Date(Web):19 Feb 2014
DOI:10.1039/C3PY01782F
A series of novel carboxyl-functionalized poly(arylene ether nitrile)s (CPAENs) were synthesized via nucleophilic substitution polycondensation reactions of 2,6-dichlorobenzonitrile with carboxyl-functionalized phenolphthalin and diphenol compounds, using N-methyl-2-pyrrolidone (NMP) as solvent in the presence of anhydrous potassium carbonate. The resulting CPAENs exhibited high glass transition temperatures ranging from 181 °C to 251 °C, and were thermally stable up to 400 °C under either nitrogen or air atmospheres. The incorporation of phenolphthalin-units into the polymer chain imparted an improved solubility of CPAENs in organic solvents, such as NMP, N,N-dimethylformamide, and tetrahydrofuran. The CPAENs were amorphous and can be readily cast into transparent films with a tensile strength of 75.1–104.7 MPa and a tensile modulus of 2.6–3.2 GPa. All CPAENs displayed a highly intense UV absorption in the wavelength range of 280–330 nm and a characteristic blue-emitting fluorescence under the UV irradiation.
Co-reporter:Xinchang Pang, Chaowei Feng, Hui Xu, Wei Han, Xukai Xin, Haiping Xia, Feng Qiu and Zhiqun Lin
Polymer Chemistry 2014 vol. 5(Issue 8) pp:2747-2755
Publication Date(Web):06 Jan 2014
DOI:10.1039/C3PY01657A
A new class of star-shaped coil–rod diblock copolymer polystyrene-block-poly(3-hexylthiophene) (PS-b-P3HT) with well-defined structures and the ratio of coil to rod blocks were synthesized by a combination of atom transfer radical polymerization, the Grignard metathesis method, and click reaction. The star-shaped PS-b-P3HT diblock copolymers covalently connected to a β-cyclodextrin (β-CD) core were composed of 21-arm coil-like PS inner blocks and rod-like conjugated polymer P3HT outer blocks with narrow molecular weight distribution. The intermediate and final products were systematically characterized and confirmed by gel permeation chromatography (GPC), 1H nuclear magnetic resonance (1H-NMR), and Fourier transfer infrared (FTIR) spectroscopy. The optical properties of star-shaped PS-b-P3HT were examined by UV-Vis absorption and photoluminescence (PL) measurements. In comparison to the linear P3HT, due to their compact structure and the introduction of PS blocks, the optical properties of 21-arm, star-shaped PS-b-P3HT were altered. The star-shaped PS-b-P3HT formed unimolecular micelles in good solvent as revealed by dynamic light scattering (DLS) and atomic force microscopy (AFM) studies.
Co-reporter:James Iocozzia, Hui Xu, Xinchang Pang, Haiping Xia, Timothy Bunning, Timothy White and Zhiqun Lin
RSC Advances 2014 vol. 4(Issue 91) pp:50212-50219
Publication Date(Web):30 Sep 2014
DOI:10.1039/C4RA09597A
A novel class of polymer, star-like poly(tert-butyl acrylate) (PtBA) capped with 4-isocyano-4′-(prop-2-yn-1-yloxy)biphenyl (CNBP), with a well-defined size was synthesized via atom transfer radical polymerization (ATRP) and click reaction (i.e., azide–alkyne cyclization). The star-like architecture was composed of 21 separate arms connected to a high-functionality β-cyclodextrin (β-CD) core. The inner star-like PtBA blocks were hydrolyzed into poly(acrylic acid) (PAA), yielding star-like CNBP-capped PAA (i.e., star-like PAA-CNBP). The starlike polymers were characterized by gel permeation chromatography (GPC) and dynamic light scattering (DLS) to confirm narrow size distribution, as well as being examined by proton nuclear magnetic resonance (1H-NMR), Fourier transform infrared spectroscopy (FTIR), Raman, and atomic force microscopy (AFM) to verify successful attachment of the click-functionalized capping agent (i.e., CNBP) with structural similarity to low molar mass liquid crystal, 4-cyano-4′-pentylbiphenyl (5CB). Structure and phase behavior were evaluated by AFM and optical imaging. Star-like PAA-CNBP was found to possess improved solubility in a liquid crystal host and interesting surface structures.
Co-reporter:Jaehan Jung;Young Jun Yoon;Ming He
Journal of Polymer Science Part B: Polymer Physics 2014 Volume 52( Issue 24) pp:1641-1660
Publication Date(Web):
DOI:10.1002/polb.23612
ABSTRACT
Semiconductor organic-inorganic nanocomposites have garnered much attention as they integrate the advantageous properties from conjugated polymers (CPs) and semiconductor nanocrystals (NCs). Recent developments in interfacial engineering of CP-NC nanocomposites enabled the intimate contact between CPs and NCs, thereby facilitating charge separation between these two constituents. To capitalize on the use of CP-NC nanocomposites for hybrid solar cells, several issues need to be addressed, including materials design and engineering, light harvesting, and morphology of photoactive layer. In this Review, the general working principle of hybrid solar cells and the development of p-type and n-type CPs are briefly introduced, followed by the highlight of recent advances in synthesis of CP-NC nanocomposites in which CP and NC are in intimate contact for hybrid solar cells, and the discussion on various strategies for potentially improved power conversion efficiency. An outlook for future directions in this area is also presented. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 1641–1660
Co-reporter:Dr. Xinchang Pang;Congshan Wan;Mengye Wang; Zhiqun Lin
Angewandte Chemie 2014 Volume 126( Issue 22) pp:5630-5644
Publication Date(Web):
DOI:10.1002/ange.201309352
Abstract
Janus-Strukturen, die nach dem antiken zweigesichtigen römischen Gott Janus benannt sind, bestehen aus zwei Halbstrukturen (z. B. Halbkugeln) mit unterschiedlichen Zusammensetzungen und Funktionalitäten. In den letzten Jahren wurde eine intensive Erforschung von Janus-Strukturen aufgrund der faszinierenden Eigenschaften und vielversprechenden potenziellen Anwendungen dieser ungewöhnlich geformten Materialien beobachtet. Dieser Aufsatz diskutiert die neuesten Fortschritte bei der Synthese, den Eigenschaften und den Anwendungen streng zweiphasiger Janus-Strukturen, die symmetrische Strukturen aufweisen, aber aus verschiedenen Materialien bestehen. Je nach chemischer Zusammensetzung können zweiphasige Janus-Strukturen in weiche, harte und hybride weiche/harte Janus-Strukturen unterschiedlichen Aufbaus – kugelförmig, stabförmig, scheibenförmig oder andersförmig – klassifiziert werden. Die wichtigsten Synthesewege zu weichen, harten und hybriden weichen/harten Janus-Strukturen werden zusammengefasst und ihre besonderen Eigenschaften und Anwendungen vorgestellt. Außerdem werden die Perspektiven der zukünftigen Forschung und Entwicklung aufgezeigt.
Co-reporter:Bo Li, Wei Han, Beibei Jiang, and Zhiqun Lin
ACS Nano 2014 Volume 8(Issue 3) pp:2936
Publication Date(Web):February 5, 2014
DOI:10.1021/nn500193y
Hierarchically assembled amphiphilic diblock copolymer micelles were exquisitely crafted over large areas by capitalizing on two concurrent self-assembling processes at different length scales, namely, the periodic threads composed of a monolayer or a bilayer of diblock copolymer micelles precisely positioned by flow-enabled self-assembly (FESA) on the microscopic scale and the self-assembly of amphiphilic diblock copolymer micelles into ordered arrays within an individual thread on the nanometer scale. A minimum spacing between two adjacent threads λmin was observed. A model was proposed to rationalize the relationship between the thread width and λmin. Such FESA of diblock copolymer micelles is remarkably controllable and easy to implement. It opens up possibilities for lithography-free positioning and patterning of diblock copolymer micelles for various applications in template fabrication of periodic inorganic nanostructures, nanoelectronics, optoelectronics, magnetic devices, and biotechnology.Keywords: amphiphilic diblock copolymer micelles; flow-enabled self-assembly; hierarchical structures; minimum spacing
Co-reporter:Rui Wang, Songping Wu, Yichao Lv, and Zhiqun Lin
Langmuir 2014 Volume 30(Issue 27) pp:8215-8220
Publication Date(Web):2017-2-22
DOI:10.1021/la501830r
Zn2GeO4 nanorod/graphene composites (ZGCs) were yielded by a two-step hydrothermal processing. Crystalline and amorphous regions were found to coexist in a single Zn2GeO4 nanorod. The surface of the Zn2GeO4 nanorod was compactly covered and anchored by graphene sheets. The ZGCs were then utilized as anodes for lithium ion batteries (LIBs). Intriguingly, partially crystalline ZGC containing 10.2 wt % graphene possessed excellent electrochemical performance, namely, high reversible capacity (1020 mA h g–1 in the first cycle), favorable cyclic performance (768 mA h g–1 after 50 cycles), and commendable rate capability (780 mA h g–1 at the current density of 0.8A g–1). The amorphous region in partially crystalline Zn2GeO4 nanorods and the elastic graphene sheets provided the accommodation of volume change during the charge and discharge processes. These advantageous attributes make ZGCs the potential anode materials for LIBs.
Co-reporter:Dr. Xinchang Pang;Congshan Wan;Mengye Wang; Zhiqun Lin
Angewandte Chemie International Edition 2014 Volume 53( Issue 22) pp:5524-5538
Publication Date(Web):
DOI:10.1002/anie.201309352
Abstract
Janus structures, named after the ancient two-faced Roman god Janus, comprise two hemistructures (e.g. hemispheres) with different compositions and functionalities. Much research has been carried out over the past few years on Janus structures because of the intriguing properties and promising potential applications of these unusually shaped materials. This Review discusses recent progress made in the synthesis, properties, and applications of strictly biphasic Janus structures possessing symmetrical structures but made of disparate materials. Depending on the chemical compositions, such biphasic structures can be categorized into soft, hard, and hybrid soft/hard Janus structures of different architectures, including spheres, rodlike, disclike, or any other shape. The main synthetic routes to soft, hard, and hybrid soft/hard Janus structures are summarized and their unique properties and applications are introduced. The perspectives for future research and development are also described.
Co-reporter:Ming He, Feng Qiu and Zhiqun Lin
Energy & Environmental Science 2013 vol. 6(Issue 5) pp:1352-1361
Publication Date(Web):11 Jan 2013
DOI:10.1039/C3EE24193A
Thermoelectric materials have garnered considerable attention due to their unique ability to directly convert heat to electricity and vice versa. Polymers carry many intrinsic advantages such as low thermal conductivity, solution processability, and roll-to-roll production for fabricating high-performance, light-weight, and flexible thermoelectric modules. In this review, we highlight recent advances in the preparation, modification and optimization of polymer thermoelectric materials, focusing especially on the current state-of-the-art strategies to minimize the thermal conductivity and maximize the power factor, and finally provide an outlook on the future development of this field.
Co-reporter:Songping Wu, Zhuolin Wang, Xin Ouyang and Zhiqun Lin
Nanoscale 2013 vol. 5(Issue 24) pp:12335-12341
Publication Date(Web):07 Oct 2013
DOI:10.1039/C3NR04638A
Size-tunable crystalline core–crystalline shell Zn2GeO4 nanorods were synthesized via a facile hydrothermal reaction. High purity Zn2GeO4 nanorods were obtained at pH = 7. The length of Zn2GeO4 nanorods (L = 50–100 nm) can be controlled through a one-step process, while micro-sized nanorods with an aspect ratio of the length to the diameter of 10 were yielded in a two-step process. The single crystalline nature of Zn2GeO4 nanorods with a core–shell structure was verified by high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) measurements. The Raman study revealed that there is no oxygen defect in Zn2GeO4 nanocrystals, suggesting that photoluminescence emission of Zn2GeO4 can be attributed to the presence of the interstitial Zn defect in Zn2GeO4 nanocrystals. As the diameter of nanorods decreased, the excitation and emission peaks appeared to be redshifted due to the quantum size effect.
Co-reporter:Xinchang Pang, Yanjie He, Beibei Jiang, James Iocozzia, Lei Zhao, Hanzheng Guo, Jin Liu, Mufit Akinc, Nicola Bowler, Xiaoli Tan and Zhiqun Lin
Nanoscale 2013 vol. 5(Issue 18) pp:8695-8702
Publication Date(Web):11 Jul 2013
DOI:10.1039/C3NR03036A
Nanocomposites composed of diblock copolymer/ferroelectric nanoparticles were formed by selectively constraining ferroelectric nanoparticles (NPs) within diblock copolymer nanodomains via judicious surface modification of ferroelectric NPs. Ferroelectric barium titanate (BaTiO3) NPs with different sizes that are permanently capped with polystyrene chains (i.e., PS-functionalized BaTiO3NPs) were first synthesized by exploiting amphiphilic unimolecular star-like poly(acrylic acid)-block-polystyrene (PAA-b-PS) diblock copolymers as nanoreactors. Subsequently, PS-functionalized BaTiO3 NPs were preferentially sequestered within PS nanocylinders in the linear cylinder-forming polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) diblock copolymer upon mixing the BaTiO3 NPs with PS-b-PMMA. The use of PS-b-PMMA diblock copolymers, rather than traditional homopolymers, offers the opportunity for controlling the spatial organization of PS-functionalized BaTiO3 NPs in the PS-b-PMMA/BaTiO3 NP nanocomposites. Selective solvent vapor annealing was utilized to control the nanodomain orientation in the nanocomposites. Vertically oriented PS nanocylinders containing PS-functionalized BaTiO3 NPs were yielded after exposing the PS-b-PMMA/BaTiO3 NP nanocomposite thin film to acetone vapor, which is a selective solvent for PMMA block. The dielectric properties of nanocomposites in the microwave frequency range were investigated. The molecular weight of PS-b-PMMA and the size of BaTiO3 NPs were found to exert an apparent influence on the dielectric properties of the resulting nanocomposites.
Co-reporter:Xukai Xin, Hsiang-Yu Liu, Meidan Ye and Zhiqun Lin
Nanoscale 2013 vol. 5(Issue 22) pp:11220-11226
Publication Date(Web):09 Sep 2013
DOI:10.1039/C3NR04370C
By combining the ease of producing ZnO nanoflowers with the advantageous chemical stability of TiO2, hierarchically structured hollow TiO2 flower-like clusters were yielded via chemical bath deposition (CBD) of ZnO nanoflowers, followed by their conversion into TiO2 flower-like clusters in the presence of TiO2 precursors. The effects of ZnO precursor concentration, precursor amount, and reaction time on the formation of ZnO nanoflowers were systematically explored. Dye-sensitized solar cells fabricated by utilizing these hierarchically structured ZnO and TiO2 flower clusters exhibited a power conversion efficiency of 1.16% and 2.73%, respectively, under 100 mW cm−2 illumination. The intensity modulated photocurrent/photovoltage spectroscopy (IMPS/IMVS) studies suggested that flower-like structures had a fast electron transit time and their charge collection efficiency was nearly 100%.
Co-reporter:Xinchang Pang, Lei Zhao, Chaowei Feng, Ruifeng Wu, Haihong Ma and Zhiqun Lin
Polymer Chemistry 2013 vol. 4(Issue 6) pp:2025-2032
Publication Date(Web):07 Jan 2013
DOI:10.1039/C2PY21124F
A series of well-defined copolymer brushes, PS-g-P3HT, composed of a hydrophobic coil-like PS backbone and densely grafted rod-like P3HT side chains were successfully synthesized by a combination of the quasi-living Grignard metathesis (GRIM) method, reversible addition–fragmentation chain transfer (RAFT), and click reaction. The molecular weight distribution of the resulting PS-g-P3HT copolymer brushes was rather narrow (polydispersity index, PDI < 1.2). The grafting efficiency was very high (i.e., the efficiency of all click reactions >96%). The self-assembly of PS-g-P3HT at the air/water interface was explored using the Langmuir–Blodgett (LB) technique. Quite intriguingly, circular domain arrays composed of the non-crystallized P3HT nanofibers were observed at high surface pressure.
Co-reporter:Lei Zhao, Chaowei Feng, Xinchang Pang, Jaehan Jung, Mihaela C. Stefan, Prakash Sista, Rui Han, Ning Fang and Zhiqun Lin
Soft Matter 2013 vol. 9(Issue 33) pp:8050-8056
Publication Date(Web):27 Jun 2013
DOI:10.1039/C3SM51488A
Controlling the self-assembly of highly luminescent conjugated polymers is essential for preparing various optoelectronic devices. In this study, a polyisoprene-b-polystyrene-b-poly(3-hexylthiophene) (PI-PS-P3HT) triblock copolymer was synthesized and readily self-assembled into network-like morphologies via dewetting at the air–water interface. Interestingly, the monolayer thick film displayed high photoluminescence (PL) as a result of successfully transferring the amorphous conjugated P3HT chains in the PI-PS-P3HT triblock copolymer from the solution state to the solid state. A model was proposed to illustrate the supramolecular organization of the PI-PS-P3HT monolayer. To the best of our knowledge, this is the first study of a hydrophobic conjugated block copolymer at the air–water interface, from which the conjugated polymer-based monolayer with highly efficient PL formed by dewetting was achieved.
Co-reporter:Jaehan Jung, Xinchang Pang, Chaowei Feng, and Zhiqun Lin
Langmuir 2013 Volume 29(Issue 25) pp:8086-8092
Publication Date(Web):April 19, 2013
DOI:10.1021/la400925y
Cadmium telluride (CdTe) tetrapods were synthesized via multiple injections of the Te precursor by utilizing bifunctional ligands. Subsequently, tetrapod-shaped semiconducting inorganic–organic nanocomposites (i.e., P3HT–CdTe tetrapod nanocomposites) were produced by directly grafting conjugated polymer ethynyl-terminated poly(3-hexylthiophene) (i.e., P3HT–≡) onto azide-functionalized CdTe tetrapods (i.e., CdTe–N3) via a catalyst-free click chemistry. The intimate contact between P3HT and CdTe tetrapod rendered the effective dispersion of CdTe tetrapods in nanocomposites and facilitated their efficient electronic interaction. The success of coupling reaction was confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. The grafting density of P3HT chains on the CdTe tetrapods was estimated by thermogravimetric analysis. The photophysical properties of P3HT–CdTe tetrapod nanocomposites were studied using UV–vis and photoluminescence spectroscopies. These intimate semiconducting conjugated polymer–tetrapod nanocomposites may offer a maximized interface between conjugated polymers and tetrapods for efficient charge separation and enhanced charge transport regardless of their orientation for potential application in hybrid solar cells with improved power conversion efficiency.
Co-reporter:Ming He, Feng Qiu, and Zhiqun Lin
The Journal of Physical Chemistry Letters 2013 Volume 4(Issue 11) pp:1788-1796
Publication Date(Web):May 14, 2013
DOI:10.1021/jz400381x
Organic–inorganic hybrid solar cells composed of conjugated polymers (CPs) and inorganic nanocrystal (NC) semiconductors have garnered considerable attention as a potential alternative to traditional silicon solar cells due to the capacity of producing high-efficiency solar energy in a cost-effective manner. The combination of advantageous characteristics of CPs and NCs enables the construction of nanostructured high-performance, lightweight, flexible, large-area, and low-cost hybrid solar cells. However, it remains a grand challenge to control the film morphology and interfacial structure of such organic/inorganic semiconductor blends on the nanoscale. In this Perspective, we highlight the strategies of implementing close contact between CPs and NCs by tailoring the colloidal synthesis, the coordination reaction, and the chemical modification of CPs. As such, they offer promising opportunities for rationally controlling the phase separation between electron-donating CPs and electron-accepting NCs, increasing the interfacial areas between them, enhancing their electronic interaction, and thus substantially promoting the photovoltaic performance of the resulting organic–inorganic hybrid solar cells.
Co-reporter:Dr. Myunghwan Byun;Dr. Wei Han;Bo Li;Dr. Xukai Xin; Zhiqun Lin
Angewandte Chemie International Edition 2013 Volume 52( Issue 4) pp:1122-1127
Publication Date(Web):
DOI:10.1002/anie.201208421
Co-reporter:Wei Han, Bo Li, and Zhiqun Lin
ACS Nano 2013 Volume 7(Issue 7) pp:6079
Publication Date(Web):June 3, 2013
DOI:10.1021/nn401885f
Large-scale highly ordered microchannels were spontaneously and rapidly created by simply drying the colloidal nanoparticle suspension on a rigid substrate. Interestingly, free evaporation of colloidal suspension yielded radially aligned microchannels, while constrained evaporation that was rendered by the use of confined geometries composed of either two nearly parallel plates or a slide placed perpendicular to a rigid substrate imparted the formation of periodic arrays of parallel microchannels in a controllable manner. The microchannels were formed as a result of the competition between stress relaxation due to crack opening that ruptured the film and stress increase due to the loss of solvent. Quite intriguingly, these patterned microchannels can be exploited as templates to craft well-ordered metallic stripes. This facile and scalable approach may offer a new paradigm of producing microscopic patterns over large areas with unprecedented regularity at low cost that can serve as scaffolds for use in microelectronics and microfluidic-based biochips, among other areas.Keywords: colloidal suspension; cracks; drying-mediated assembly; microchannels
Co-reporter:Bo Li, Wei Han, Myunghwan Byun, Lei Zhu, Qingze Zou, and Zhiqun Lin
ACS Nano 2013 Volume 7(Issue 5) pp:4326
Publication Date(Web):April 4, 2013
DOI:10.1021/nn400840y
By subjecting DNA aqueous solution to evaporate in a curve-on-flat geometry that was composed of either a spherical lens or a cylindrical lens situated on a flat substrate, a set of highly aligned DNA nanowires in the forms of spokes and parallel stripes over a macroscopic area (i.e., millimeter scale) were successfully created. The DNA molecules were stretched and aligned on polymer-coated substrate by the receding meniscus. The imposed curve-on-flat geometry provided a unique environment for controlling the flow within the evaporating solution by eliminating temperature gradient and possible convective instability and, thus, regulated the formation of DNA nanowires. Such controlled evaporative self-assembly is remarkably easy to implement and opens up a new avenue for crafting large-scale DNA-based nanostructures in a simple and cost-effective manner, dispensing with the need for lithography techniques.Keywords: confined geometry; controlled evaporation self-assembly; DNA nanowire
Co-reporter:Dr. Wei Han;Dr. Ming He;Dr. Myunghwan Byun;Bo Li; Zhiqun Lin
Angewandte Chemie International Edition 2013 Volume 52( Issue 9) pp:2564-2568
Publication Date(Web):
DOI:10.1002/anie.201209632
Co-reporter:Dr. Myunghwan Byun;Dr. Wei Han;Bo Li;Dr. Xukai Xin; Zhiqun Lin
Angewandte Chemie 2013 Volume 125( Issue 4) pp:1160-1165
Publication Date(Web):
DOI:10.1002/ange.201208421
Co-reporter:Dr. Wei Han;Dr. Ming He;Dr. Myunghwan Byun;Bo Li; Zhiqun Lin
Angewandte Chemie 2013 Volume 125( Issue 9) pp:2624-2628
Publication Date(Web):
DOI:10.1002/ange.201209632
Co-reporter:Lei Zhao
Advanced Materials 2012 Volume 24( Issue 32) pp:4353-4368
Publication Date(Web):
DOI:10.1002/adma.201201196
Abstract
Semiconductor organic−inorganic hybrid solar cells incorporating conjugated polymers (CPs) and nanocrystals (NCs) offer the potential to deliver efficient energy conversion with low-cost fabrication. The CP-based photovoltaic devices are complimented by an extensive set of advantageous characteristics from CPs and NCs, such as lightweight, flexibility, and solution-processability of CPs, combined with high electron mobility and size-dependent optical properties of NCs. Recent research has witnessed rapid advances in an emerging field of directly tethering CPs on the NC surface to yield an intimately contacted CP−NC nanocomposite possessing a well-defined interface that markedly promotes the dispersion of NCs within the CP matrix, facilitates the photoinduced charge transfer between these two semiconductor components, and provides an effective platform for studying the interfacial charge separation and transport. In this Review, we aim to highlight the recent developments in CP−NC nanocomposite materials, critically examine the viable preparative strategies geared to craft intimate CP−NC nanocomposites and their photovoltaic performance in hybrid solar cells, and finally provide an outlook for future directions of this extraordinarily rich field.
Co-reporter:Lei Zhao
Advanced Materials 2012 Volume 24( Issue 32) pp:
Publication Date(Web):
DOI:10.1002/adma.201290194
Co-reporter:Yoon Hee Jang, Xukai Xin, Myunghwan Byun, Yu Jin Jang, Zhiqun Lin, and Dong Ha Kim
Nano Letters 2012 Volume 12(Issue 1) pp:479-485
Publication Date(Web):December 12, 2011
DOI:10.1021/nl203901m
Graphitic thin films embedded with highly dispersed titanium dioxide (TiO2) nanoparticles were incorporated for the first time into the conventional dye-sensitized solar cells (DSSCs), resulting in a remarkably improved cell efficiency due to its superior electron conductivity. Massively ordered arrays of TiO2 dots embedded in carbon matrix were fabricated via UV-stabilization of polystyrene-block-poly(4-vinylpyridine) films containing TiO2 precursors followed by direct carbonization. For dye-sensitized TiO2 based solar cells containing carbon/TiO2 thin layers at both sides of pristine TiO2 layer, an increase of 40.6% in overall power conversion efficiency was achieved compared with neat TiO2-based DSSCs. Such a remarkably improved cell efficiency was ascribed to the superior electron conductivity and extended electron lifetime elucidated by cyclic voltammetry and impedance spectroscopy.
Co-reporter:Meidan Ye ; Jiaojiao Gong ; Yuekun Lai ; Changjian Lin
Journal of the American Chemical Society 2012 Volume 134(Issue 38) pp:15720-15723
Publication Date(Web):September 10, 2012
DOI:10.1021/ja307449z
TiO2 nanotube arrays (TNTAs) sensitized by palladium quantum dots (Pd QDs) exhibit highly efficient photoelectrocatalytic hydrogen generation. Vertically oriented TNTAs were prepared by a three-step electrochemical anodization. Subsequently, Pd QDs with uniform size and narrow size distribution were formed on TiO2 nanotubes by a modified hydrothermal reaction (i.e., yielding nanocomposites of Pd QDs deposited on TNTAs, Pd@TNTAs). By exploiting Pd@TNTA nanocomposites as both photoanode and cathode, a substantially increased photon-to-current conversion efficiency of nearly 100% at λ = 330 nm and a greatly promoted photocatalytic hydrogen production rate of 592 μmol·h–1·cm–2 under 320 mW·cm–2 irradiation were achieved. The synergy between nanotubular structures of TiO2 and uniformly dispersed Pd QDs on TiO2 facilitated the charge transfer of photoinduced electrons from TiO2 nanotubes to Pd QDs and the high activity of Pd QDs catalytic center, thereby leading to high-efficiency photoelectrocatalytic hydrogen generation.
Co-reporter:Ming He, Jaehan Jung, Feng Qiu and Zhiqun Lin
Journal of Materials Chemistry A 2012 vol. 22(Issue 46) pp:24254-24264
Publication Date(Web):13 Jul 2012
DOI:10.1039/C2JM33784C
Conjugated polymer-based bulk heterojunction (BHJ) solar cells are widely recognized as a promising alternative to their inorganic counterparts for achieving low-cost, roll-to-roll production of large-area flexible lightweight photovoltaic devices. Current research in designing new polymers and optimizing device architectures has been devoted to improving the film morphology, photovoltaic performance and stability of polymer BHJ solar cells. Conjugated block copolymers (BCPs), including rod–coil and rod–rod BCPs, exhibit excellent flexibility for tuning the bandgap of semiconductor polymers, regulating the molecular organization of donor (and/or acceptor) units, templating the film morphology of active layers, and achieving well-defined BHJ architectures. In this Feature Article, we summarize the recent developments over the past five years in the synthesis, self-assembly, and utilization of conjugated rod–coil and all-conjugated rod–rod BCPs for solar energy conversion; highlight the correlation between the microphase-separated morphology and photovoltaic properties in conjugated BCPs; and finally provide an outlook on the future of BCP-based photovoltaic devices.
Co-reporter:Xukai Xin, Jun Wang, Wei Han, Meidan Ye and Zhiqun Lin
Nanoscale 2012 vol. 4(Issue 3) pp:964-969
Publication Date(Web):21 Dec 2011
DOI:10.1039/C2NR11617K
Dye-sensitized solar cells (DSSCs) were prepared by capitalizing on a TiO2 bilayer structure composed of P-25 nanoparticles and freestanding crystalline nanotube arrays as photoanodes. After being subjected to sequential TiCl4 treatment and O2 plasma exposure, the bilayer photoanode was sensitized with N719 dye. DSSCs based on a 20 μm TiO2 nanoparticle film solely and a bilayer of 13 μm TiO2 nanoparticles and 7 μm TiO2 nanotubes exhibited the highest power conversion efficiency, PCE, of 8.02% and 7.00%, respectively, compared to the devices made of different TiO2 thicknesses. On the basis of J–V parameter analysis acquired by equivalent circuit model simulation, in comparison to P-25 nanoparticles, charge transport in nanotubes was found to be facilitated due to the presence of advantageous nanotubular structures, while photocurrent was reduced owing to their small surface area, which in turn resulted in low dye loading, as well as the lack of cooperative effect of anatase and rutile phases.
Co-reporter:Wei Han ; Zhiqun Lin
Angewandte Chemie International Edition 2012 Volume 51( Issue 7) pp:1534-1546
Publication Date(Web):
DOI:10.1002/anie.201104454
Abstract
Research into the evaporation of solutions is not only aimed at a better understanding the physics of evaporation, but increasingly at capitalizing on the extremely simple method it offers to assemble diverse nonvolatile solutes into complex ordered structures on the submicron and longer length scales. This Review highlights recent advances in evaporative assembly of confined solutions, focusing especially on recently developed approaches that provide structures with unprecedented regularity composed of polymers, nanoparticles, and biomaterials, by controlled evaporation-driven, flow-aided self-assembly. A broad range of variables that can control the deposition are explored and the future directions of this rich field are presented.
Co-reporter:Dr. Wei Han;Dr. Myunghwan Byun;Bo Li;Dr. Xinchang Pang; Zhiqun Lin
Angewandte Chemie International Edition 2012 Volume 51( Issue 50) pp:12588-12592
Publication Date(Web):
DOI:10.1002/anie.201207902
Co-reporter:Dr. Wei Han;Dr. Myunghwan Byun;Bo Li;Dr. Xinchang Pang; Zhiqun Lin
Angewandte Chemie 2012 Volume 124( Issue 50) pp:12756-12760
Publication Date(Web):
DOI:10.1002/ange.201207902
Co-reporter:Wei Han ; Zhiqun Lin
Angewandte Chemie 2012 Volume 124( Issue 7) pp:1566-1579
Publication Date(Web):
DOI:10.1002/ange.201104454
Abstract
Trocknende Lösungen sind nicht nur ein Modell für die Untersuchung des Verdunstungsvorgangs an sich, sondern sie lassen sich auch nutzen, um nichtflüchtige gelöste Stoffe zu komplexen geordneten Strukturen im Submikrometermaßstab und darüber zu aggregieren. Dieser Aufsatz behandelt aktuelle Fortschritte bei der Verdunstungsaggregation aus räumlich eingeschränkten Lösungen mit besonderem Augenmerk auf neuen präparativen Ansätzen zur Herstellung von Strukturen mit höchster Regelmäßigkeit aus Polymeren, Nanopartikeln und Biomaterialien über kontrollierte verdunstungsgetriebene strömungsunterstützte Selbstorganisation. Die Abscheidung kann über verschiedene Variablen kontrolliert werden. Schließlich wird ein Ausblick auf zukünftige Entwicklungen auf diesem faszinierenden Gebiet gegeben.
Co-reporter:Dr. Jun Wang; Zhiqun Lin
Chemistry – An Asian Journal 2012 Volume 7( Issue 12) pp:2754-2762
Publication Date(Web):
DOI:10.1002/asia.201200349
Abstract
Owing to well-defined structural parameters and enhanced electronic properties, highly ordered TiO2 nanotube arrays have been employed to substitute TiO2 nanoparticles for use in dye-sensitized solar cells. To further improve the performance of dye-sensitized TiO2 nanotube solar cells, efforts have been directed toward the optimization of TiO2 photoanodes, dyes, electrolytes, and counter electrodes. Herein, we highlight recent progress in rational structural and surface engineering on anodic TiO2 nanotube arrays and their effects on improving the power conversion efficiency of dye-sensitized TiO2 nanotube solar cells.
Co-reporter:Ming He, Wei Han, Jing Ge, Yuliang Yang, Feng Qiu and Zhiqun Lin
Energy & Environmental Science 2011 vol. 4(Issue 8) pp:2894-2902
Publication Date(Web):30 Jun 2011
DOI:10.1039/C1EE01509E
Control over the ratio of two blocks in a new class of all-conjugated diblock copolymers, poly(3-butylthiophene)-b-poly(3-hexylthiophene) (P3BHT), provides a facile approach to precisely tune the molecular organization and nanoscale morphology in polymer bulk heterojunction (BHJ) solar cells. In stark contrast to the power conversion efficiency, PCE, of 1.08% in poly(3-butylthiophene) (P3BT)/[6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) and 3.54% in poly(3-hexylthiophene) (P3HT)/PC71BM solar cells, an attractive, high PCE of 4.02% was achieved in a P3BHT21/PC71BM BHJ device in which the molar ratio of P3BT:P3HT in P3BHT21 was 2:1. The ratio of P3BT and P3HT blocks was found to exert a noteworthy influence on the molecular organization of P3BHT, the film morphology of P3BHT/PC71BM blend, and the final performance of P3BHT/PC71BM photovoltaic devices. This enhanced performance reflected a synergy of finer phase separation of P3BHT21 and PC71BM and the formation of respective percolation networks of electron donor P3BHT and electron acceptor PC71BM. The P3HT block rendered the P3BHT chains with favorable chemical compatibility for the diffusion of PC71BM molecules, allowing for finer phase separation between P3BHT crystalline domains and PC71BM domains at the nanoscale and maximizing the interfacial area of P3BHT21/PC71BM for improved charge generation. The P3BT block facilitated the self-assembly of P3BHT chains into sufficient interpenetrating pathways for efficient charge transport and collection. Moreover, a small crystalline domain with a size of 10.4 nm formed in the active layer that is comparable to the exciton diffusion length of most conjugated polymers (∼10 nm).
Co-reporter:Meidan Ye, Xukai Xin, Changjian Lin, and Zhiqun Lin
Nano Letters 2011 Volume 11(Issue 8) pp:3214-3220
Publication Date(Web):July 5, 2011
DOI:10.1021/nl2014845
Dye-sensitized solar cells (DSSCs) based on hierarchically structured TiO2 nanotubes prepared by a facile combination of two-step electrochemical anodization with a hydrothermal process exhibited remarkable performance. Vertically oriented, smooth TiO2 nanotube arrays fabricated by a two-step anodic oxidation were subjected to hydrothermal treatment, thereby creating advantageous roughness on the TiO2 nanotube surface (i.e., forming hierarchically structured nanotube arrays—nanoscopic tubes composed of a large number of nanoparticles on the surface) that led to an increased dye loading. Subsequently, these nanotubes were exploited to produce DSSCs in a backside illumination mode, yielding a significantly high power conversion efficiency, of 7.12%, which was further increased to 7.75% upon exposure to O2 plasma.
Co-reporter:Ming He, Feng Qiu and Zhiqun Lin
Journal of Materials Chemistry A 2011 vol. 21(Issue 43) pp:17039-17048
Publication Date(Web):02 Aug 2011
DOI:10.1039/C1JM11518A
Conjugated polymer-based bulk heterojunction (BHJ) solar cells are widely recognized as a promising alternative to their inorganic counterparts for achieving low-cost, roll-to-roll production of large-area flexible lightweight photovoltaic devices. Current research in designing new polymers and optimizing device architectures has been devoted to improving the film morphology, photovoltaic performance and stability of polymer BHJ solar cells. Conjugated block copolymers (BCPs), including rod–coil and rod–rod BCPs, exhibit excellent flexibility for tuning the band gap of semiconductor polymers, regulating the molecular organization of donor (and/or acceptor) units, templating the film morphology of active layers, and achieving well-defined BHJ architectures. In this Feature Article, we summarize the recent developments over the past five years in the synthesis, self-assembly, and utilization of conjugated rod–coil and all-conjugated rod–rod BCPs for solar energy conversion, highlight the correlation between the microphase-separated morphology and photovoltaic properties in conjugated BCPs, and finally provide an outlook on the future of BCP-based photovoltaic devices.
Co-reporter:Wei Han, Myunghwan Byun and Zhiqun Lin
Journal of Materials Chemistry A 2011 vol. 21(Issue 42) pp:16968-16972
Publication Date(Web):05 Aug 2011
DOI:10.1039/C1JM11603G
By capitalizing on a simple, robust, and fast approach based on controlled evaporative self-assembly in a cylinder-on-flat geometry, two kinds of polystyrene (PS) latex nanoparticles with different diameters (i.e., D = 50 nm and 500 nm, respectively) were deposited on the Si substrate, forming ordered “coffee rings” composed of PS nanoparticles. Within a “coffee ring”, the packing of PS nanoparticles was found to be dependent upon the particle diameter. More intriguingly, when the aqueous solution of mixed two PS nanoparticles was used, “coffee rings” of small particles were positioned at the edge of three-phase contact line (D = 50 nm), followed by the adjacent deposition of large particles (D = 500 nm). These assembled deposits consisting of monolayer- or multilayer-thick latex nanoparticles over large areas may offer potential for applications in electronic devices, photonic bandgap materials, biosensors, particle sorting, and disease diagnosis.
Co-reporter:Ming He, Wei Han, Jing Ge, Weijie Yu, Yuliang Yang, Feng Qiu and Zhiqun Lin
Nanoscale 2011 vol. 3(Issue 8) pp:3159-3163
Publication Date(Web):30 Jun 2011
DOI:10.1039/C1NR10293A
The effects of thermal and solvent vapor annealing on the photovoltaic performance of a new class of all-conjugated poly(3-butylthiophene)-b-poly(3-hexylthiophene) diblock copolymer/PC71BM bulk heterojunction (BHJ) solar cells were scrutinized and theoretically analyzed using the single diode model combined with experimental measurements. The meanings of physical parameters in the model were elucidated in the context of crystalline order and phase separation to gain fundamental insight into the mechanism of annealing effects on the device performance of a new class of all-conjugated diblock copolymer-based BHJ solar cells.
Co-reporter:Xukai Xin;Dr. Ming He;Wei Han;Jaehan Jung; Zhiqun Lin
Angewandte Chemie 2011 Volume 123( Issue 49) pp:11943-11946
Publication Date(Web):
DOI:10.1002/ange.201104786
Co-reporter:Xinchang Pang, Lei Zhao, Chaowei Feng, and Zhiqun Lin
Macromolecules 2011 Volume 44(Issue 18) pp:7176-7183
Publication Date(Web):September 2, 2011
DOI:10.1021/ma201564t
A series of novel amphiphilic 21-arm, starlike diblock copolymers, poly(acrylic acid)-b-poly(3-hexylthiophene) (PAA-b-P3HT), based on β-cyclodextrin (β-CD) with well-defined molecular architectures and ratio of two chemically distinct blocks were prepared, for the first time, via a combination of quasi-living Grignard metathesis method (GRIM), click reaction, and atom transfer radical polymerization (ATRP). The starlike PAA-b-P3HT diblock copolymers consist of hydrophilic coil-like PAA cores and hydrophobic rodlike P3HT shells with narrow molecular weight distribution and well-defined molecular weight of each block. Owing to the compact structure, the amphiphilic starlike PAA-b-P3HT formed a unimolecular micelle. Emulsion based on these novel amphiphilic starlike, coil–rod diblock copolymers were readily produced by cross-linking hydrophilic coil-like PAA cores with a bifunctional cross-linker, ethylenediamine.
Co-reporter:Xukai Xin;Dr. Ming He;Wei Han;Jaehan Jung; Zhiqun Lin
Angewandte Chemie International Edition 2011 Volume 50( Issue 49) pp:11739-11742
Publication Date(Web):
DOI:10.1002/anie.201104786
Co-reporter:Xukai Xin;Dr. Ming He;Wei Han;Jaehan Jung; Zhiqun Lin
Angewandte Chemie International Edition 2011 Volume 50( Issue 49) pp:
Publication Date(Web):
DOI:10.1002/anie.201106048
Co-reporter:Xukai Xin;Dr. Ming He;Wei Han;Jaehan Jung; Zhiqun Lin
Angewandte Chemie 2011 Volume 123( Issue 49) pp:
Publication Date(Web):
DOI:10.1002/ange.201106048
Co-reporter:Xukai Xin, Margaret Scheiner, Meidan Ye, and Zhiqun Lin
Langmuir 2011 Volume 27(Issue 23) pp:14594-14598
Publication Date(Web):October 20, 2011
DOI:10.1021/la2034627
Dye-sensitized solar cells (DSSCs) were prepared by capitalizing on mesoporous P-25 TiO2 nanoparticle film sensitized with N719 dyes. Subjecting TiO2 nanoparticle films to TiCl4 treatment, the device performance was improved. More importantly, O2 plasma processing of TiO2 film that was not previously TiCl4-treated resulted in a lower efficiency; by contrast, subsequent O2 plasma exposure after TiCl4 treatment markedly enhanced the power conversion efficiency, PCE, of DSSCs. Remarkably, with TiCl4 and O2 plasma treatments dye-sensitized TiO2 nanoparticle solar cells produced with 21 μm thick TiO2 film illuminated under 100 mW/cm2 exhibited a PCE as high as 8.35%, twice of untreated cells of 3.86%.
Co-reporter:Ping Ye, Xinling Liu, James Iocozzia, Yupeng Yuan, Lina Gu, Gengsheng Xu and Zhiqun Lin
Journal of Materials Chemistry A 2017 - vol. 5(Issue 18) pp:NaN8498-8498
Publication Date(Web):2017/04/04
DOI:10.1039/C7TA01031A
Nickel phosphide (Ni2P) was grown on a graphitic carbon nitride (g-C3N4) surface by annealing a mixture of g-C3N4, NiCl2, and NaH2PO2 at 400 °C for 2 h in an Ar atmosphere. During the annealing, Ni2P particles formed intimate interfaces with g-C3N4. As a result, charge transfer from photo-excited g-C3N4 to Ni2P was improved as demonstrated by the improved photocatalytic H2 generation (40.5 μmol h−1 g−1) compared to a physical mixture of Ni2P and g-C3N4 (trace H2 generation). Under optimal and identical experimental conditions, the H2 production rate on Ni2P-loaded g-C3N4 (2 wt%) is 82.5 μmol h−1 g−1, which is higher than that of Pt-loaded g-C3N4 (0.5 wt%) (72 μmol h−1 g−1). Impressively, Ni2P shows a highly stable H2 production activity despite being a non-noble metal co-catalyst. No activity loss occurs over repeated use and 24 h long-term H2 generation trials. In contrast, a pronounced reduction in H2 generation was observed for Pt-loaded g-C3N4 (0.5 wt%) over the same 24 hour trial period. Among their many advantages, including non-toxicity, low cost and natural abundance, Ni2P/g-C3N4 composites are a promising alternative for realizing efficient, long-lasting photocatalytic H2 production.
Co-reporter:Bo Li, Beibei Jiang, Haillong Tang and Zhiqun Lin
Chemical Science (2010-Present) 2015 - vol. 6(Issue 11) pp:NaN6354-6354
Publication Date(Web):2015/07/20
DOI:10.1039/C5SC02337H
Ultrathin Au nanowires have garnered increasing attention in recent years because of their potential use in a range of applications due to their unique optical properties, conductivity, chemical activity, and discrete plasticity. Herein, we report an unconventional seed-mediated growth of ultrathin Au nanowires induced by hydrophobic molecules. Quite intriguingly, by adding a trace amount of hydrophobic molecules (i.e., toluene or chloroform) to the Au growth solution conventionally used for the growth of Au nanorods with cylindrical CTAB micelles as templates, CTAB-capped ultrathin Au nanowires (i.e., water-soluble ultrathin Au nanowires) were crafted. Similarly to the growth of Au nanorods, silver ions and Au seeds were crucially required to yield the water-soluble ultrathin Au nanowires. The growth mechanism of these ultrathin nanowires was also explored.
Co-reporter:Mengye Wang, Xinchang Pang, Dajiang Zheng, Yanjie He, Lan Sun, Changjian Lin and Zhiqun Lin
Journal of Materials Chemistry A 2016 - vol. 4(Issue 19) pp:NaN7199-7199
Publication Date(Web):2016/03/18
DOI:10.1039/C6TA01838F
The ability to synthetically tune the size, shape, composition and architecture of inorganic nanostructures offers enormous opportunities to explore the fundamental structure–property relationships that occur uniquely at the nanoscale, and engineer greater functionality and design complexity into new material systems. Core/shell nanoparticles represent an important class of nanostructured materials that have garnered considerable interest. The success in producing core/shell nanoparticles with strictly controlled core diameter and shell thickness and tailoring their material properties relies crucially on the epitaxial growth of the shell material over the highly curved surface of the spherical core. However, effective methods to yield such high-quality core/shell nanoparticles are comparatively few and limited in scope. Here, we develop a robust nonepitaxial growth strategy to create uniform plasmonic/semiconducting core/shell nanoparticles with precisely controlled dimensions by capitalizing on amphiphilic star-like triblock copolymers as nanoreactors. The diameter of the plasmonic core and the thickness of the semiconductor shell can be independently and precisely regulated by tailoring the molecular weights (i.e., the lengths) of the inner and intermediate blocks of star-like triblock copolymers, respectively. The successful crafting of plasmonic/semiconducting core/shell nanoparticles was corroborated by the composition and structural characterizations. These functional nanoparticles exhibited largely improved photocatalytic activities, which can be attributed to the localized surface plasmon-mediated light harvesting enhancement of the plasmonic core and the built-in internal electric field. This nonepitaxial growth strategy offers new levels of tailorability in the dimensions, compositions and architectures of nanomaterials with engineered functionalities for applications in catalytic, electronic, optic, optoelectronic and sensory materials and devices.
Co-reporter:Ming He, Jaehan Jung, Feng Qiu and Zhiqun Lin
Journal of Materials Chemistry A 2012 - vol. 22(Issue 46) pp:NaN24264-24264
Publication Date(Web):2012/07/13
DOI:10.1039/C2JM33784C
Conjugated polymer-based bulk heterojunction (BHJ) solar cells are widely recognized as a promising alternative to their inorganic counterparts for achieving low-cost, roll-to-roll production of large-area flexible lightweight photovoltaic devices. Current research in designing new polymers and optimizing device architectures has been devoted to improving the film morphology, photovoltaic performance and stability of polymer BHJ solar cells. Conjugated block copolymers (BCPs), including rod–coil and rod–rod BCPs, exhibit excellent flexibility for tuning the bandgap of semiconductor polymers, regulating the molecular organization of donor (and/or acceptor) units, templating the film morphology of active layers, and achieving well-defined BHJ architectures. In this Feature Article, we summarize the recent developments over the past five years in the synthesis, self-assembly, and utilization of conjugated rod–coil and all-conjugated rod–rod BCPs for solar energy conversion; highlight the correlation between the microphase-separated morphology and photovoltaic properties in conjugated BCPs; and finally provide an outlook on the future of BCP-based photovoltaic devices.
Co-reporter:Wei Han, Myunghwan Byun and Zhiqun Lin
Journal of Materials Chemistry A 2011 - vol. 21(Issue 42) pp:NaN16972-16972
Publication Date(Web):2011/08/05
DOI:10.1039/C1JM11603G
By capitalizing on a simple, robust, and fast approach based on controlled evaporative self-assembly in a cylinder-on-flat geometry, two kinds of polystyrene (PS) latex nanoparticles with different diameters (i.e., D = 50 nm and 500 nm, respectively) were deposited on the Si substrate, forming ordered “coffee rings” composed of PS nanoparticles. Within a “coffee ring”, the packing of PS nanoparticles was found to be dependent upon the particle diameter. More intriguingly, when the aqueous solution of mixed two PS nanoparticles was used, “coffee rings” of small particles were positioned at the edge of three-phase contact line (D = 50 nm), followed by the adjacent deposition of large particles (D = 500 nm). These assembled deposits consisting of monolayer- or multilayer-thick latex nanoparticles over large areas may offer potential for applications in electronic devices, photonic bandgap materials, biosensors, particle sorting, and disease diagnosis.
Co-reporter:Ming He, Feng Qiu and Zhiqun Lin
Journal of Materials Chemistry A 2011 - vol. 21(Issue 43) pp:NaN17048-17048
Publication Date(Web):2011/08/02
DOI:10.1039/C1JM11518A
Conjugated polymer-based bulk heterojunction (BHJ) solar cells are widely recognized as a promising alternative to their inorganic counterparts for achieving low-cost, roll-to-roll production of large-area flexible lightweight photovoltaic devices. Current research in designing new polymers and optimizing device architectures has been devoted to improving the film morphology, photovoltaic performance and stability of polymer BHJ solar cells. Conjugated block copolymers (BCPs), including rod–coil and rod–rod BCPs, exhibit excellent flexibility for tuning the band gap of semiconductor polymers, regulating the molecular organization of donor (and/or acceptor) units, templating the film morphology of active layers, and achieving well-defined BHJ architectures. In this Feature Article, we summarize the recent developments over the past five years in the synthesis, self-assembly, and utilization of conjugated rod–coil and all-conjugated rod–rod BCPs for solar energy conversion, highlight the correlation between the microphase-separated morphology and photovoltaic properties in conjugated BCPs, and finally provide an outlook on the future of BCP-based photovoltaic devices.
Co-reporter:Songping Wu, Yichao Lv, Mingjia Lu and Zhiqun Lin
Journal of Materials Chemistry A 2015 - vol. 3(Issue 13) pp:NaN3127-3127
Publication Date(Web):2015/02/11
DOI:10.1039/C4TC02828G
Multiferroic ErMn2O5 nanorods have been synthesized via a surfactant-templated hydrothermal route. An environmentally friendly natural surfactant (Arabic gum) has been utilized as a template to prepare ErMn2O5 nanorods with a controllable morphology and size (i.e., nanorods with various lengths and basically invariable diameter). ErMn2O5 nanorods show strong size-dependent magnetic properties that correlate with: (a) a critical length for magnetization, and (b) recognizable divagation between FC and ZFC curves at low temperature. The former could be ascribed to the competition between surface strain and uncompensated spin at the surface, and the latter to Er antiferromagnetic ordering.
Co-reporter:Ming He, Dajiang Zheng, Mengye Wang, Changjian Lin and Zhiqun Lin
Journal of Materials Chemistry A 2014 - vol. 2(Issue 17) pp:NaN6003-6003
Publication Date(Web):2013/11/01
DOI:10.1039/C3TA14160H
Perovskite solar cells have garnered great attention in recent years as promising high performance next-generation solar cells with long-term stability at low cost. Since the seminal work of Miyasaka and others in 2009, the power conversion efficiency (PCE) of perovskite-based dye-sensitized solar cells (DSSCs) has rapidly increased from 3.8% to 15% over the past four years, exceeding the highest efficiency of conventional organic dye-sensitized DSSCs. Recently, the perovskite has been demonstrated to act successfully as an active layer in simple planar-heterojunction solar cells with no need of complex nanostructured DSSC architectures, leading to an attractively high PCE of 15.4% at a competitive low manufacturing cost. In this Feature Article, we aim to review the recent impressive development in perovskite solar cells, and discuss the prognosis for future progress in exploiting perovskite materials for high efficiency solar cells.
Co-reporter:Wenming Liao, Dajiang Zheng, Jianhua Tian and Zhiqun Lin
Journal of Materials Chemistry A 2015 - vol. 3(Issue 46) pp:NaN23367-23367
Publication Date(Web):2015/10/05
DOI:10.1039/C5TA06238A
Upconversion/semiconductor submicron hollow spheres composed of inner NaxGdFyOz:Yb/Er shell and outer TiO2 shell (denoted NaxGdFyOz:Yb/Er@TiO2) were, for the first time, crafted by exploiting colloidal carbon spheres as the scaffold. The hollow spheres were then incorporated into the TiO2 nanoparticle film photoanode to yield dye-sensitized solar cells (DSSCs) with improved performance. The implementation of NaxGdFyOz:Yb/Er@TiO2 hollow spheres in DSSCs imparted the light trapping due to the light scattering from submicron hollow spheres, and the harvesting of near infrared solar photons by the upconversion material (i.e., dual functionalities), thereby resulting in an increased short-circuit current density Jsc, and thus an improved power conversion efficiency PCE. The electrochemical impedance spectroscopy measurements were performed to scrutinize the interfacial charge transfer characteristics of DSSCs. The measurements revealed that when NaxGdFyOz:Yb/Er hollow spheres without the deposition of TiO2 shell were integrated in the photoanode, a high charge transfer resistance was found. In stark contrast, the judicious decoration of NaxGdFyOz:Yb/Er hollow spheres with a thin layer of TiO2 shell markedly improved the contact between the resulting NaxGdFyOz:Yb/Er@TiO2 shell/shell hollow spheres and the TiO2 nanoparticle film photoanode, leading to a much decreased charge transfer resistance. Taken together, compared to the PCE of 6.81% for the pristine device, the DSSC assembled with the introduction of 8 wt% NaxGdFyOz:Yb/Er@TiO2 hollow spheres in the photoanode exhibited an optimal PCE of 7.58% and a maximum short-circuit current density Jsc of 18.72 mA cm−2 under AM 1.5G one sun illumination, corresponding to 11.31% performance enhancement. As such, the implementation of upconversion submicron hollow materials in photoanode may stand out as an intriguing strategy to improve the device performance of DSSCs.
Co-reporter:Xiong Zhang, Yuekun Lai, Mingzheng Ge, Yaxin Zheng, Ke-Qin Zhang and Zhiqun Lin
Journal of Materials Chemistry A 2015 - vol. 3(Issue 25) pp:NaN13577-13577
Publication Date(Web):2015/06/04
DOI:10.1039/C5TA90128F
Correction for ‘Fibrous and flexible supercapacitors comprising hierarchical nanostructures with carbon spheres and graphene oxide nanosheets’ by Xiong Zhang et al., J. Mater. Chem. A, 2015, DOI: 10.1039/c5ta03252k.
Co-reporter:Cuiping Han, Di Yang, Yingkui Yang, Beibei Jiang, Yanjie He, Mengye Wang, Ah-Young Song, Yan-Bing He, Baohua Li and Zhiqun Lin
Journal of Materials Chemistry A 2015 - vol. 3(Issue 25) pp:NaN13349-13349
Publication Date(Web):2015/05/15
DOI:10.1039/C5TA02070K
By subjecting amorphous titanium dioxide (TiO2) colloidal spheres as a scaffold to a two-step external template-free hydrothermal treatment, anatase TiO2 hollow spheres with an average diameter of 410 nm and shell thickness of 65 nm were successfully yielded. Such hollow TiO2 nanostructures possessed a large surface area, abundant active sites and reduced Li ion diffusion path and thus were highly favorable for use in TiO2-based lithium ion batteries (LIB). Electrochemical measurements revealed that as-prepared TiO2 hollow spheres exhibited specific discharge capacities of 296, 185, 118, 66 and 37 mA h g−1 at 0.1 C, 1 C, 2 C, 5 C and 10 C, respectively. This is in sharp contrast to the considerably lower values obtained in TiO2 solid nanoparticles (i.e., 182, 119, 81, 43 18 mA h g−1 at discharge rates of 0.1 C, 1 C, 2 C, 5 C and 1 0 C, respectively). Interestingly, TiO2 hollow spheres showed a large irreversible capacity loss and relatively low cycling performance due to the residual chemisorbed water in TiO2 and hydroxyl groups present on the TiO2 surface. A solid electrolyte interface (SEI) layer composed primarily of Li2CO3, lithium alkyl carbonates and organic phosphates was thus formed on the surface of hollow TiO2 spheres, thereby leading to an increased internal cell impedance and the decreased rate and cycling performance. The subsequent high-temperature annealing effectively removed chemisorbed water and hydroxyls on the TiO2 surface. As a consequence, annealed TiO2 hollow spheres rendered markedly improved rate stability and cycle performance in the resulting TiO2-based LIBs. The specific discharge capacities at rates of 5 C and 10 C were 77 mA h g−1 and 50 mA h g−1, which are considerably larger than those obtained from as-prepared TiO2 hollow spheres. Moreover, compared to only 42.1% for as-prepared hollow TiO2 spheres, a capacity retention as high as 93.5% over 200 cycles at 1 C was achieved for annealed hollow TiO2 spheres.
Co-reporter:Xueqin Liu, Zhen Li, Wen Zhao, Caixin Zhao, Yang Wang and Zhiqun Lin
Journal of Materials Chemistry A 2015 - vol. 3(Issue 37) pp:NaN19154-19154
Publication Date(Web):2015/08/12
DOI:10.1039/C5TA05508C
Reduced graphene oxide (rGO)-wrapped octahedral Cu2O composites (GCCs) were successfully produced by an ultrasonication-assisted reduction of graphene oxide (GO) in the Cu2O precursor solution. During the ultrasound reaction, the reduction of GO and the growth of octahedral Cu2O crystals occurred simultaneously in conjunction with the deposition of Cu2O crystals on graphene. As a result of the introduction of rGO, the light absorption of octahedral Cu2O was markedly improved, the size of Cu2O crystals was decreased, and the self-aggregation of Cu2O crystals was effectively prevented. More importantly, the charge separation and transfer were effectively enhanced. Compared to the pure octahedral Cu2O crystals and commercial TiO2 (P25), the GCCs exhibited an increased degradation rate of methyl orange (MO) by 4.5 and 20.2 times, respectively. Meanwhile, upon the graphene loading, the photoelectric conversion efficiency of GCC electrodes was largely improved resulting in an efficiency of 0.151%, representing an 8 fold higher efficiency than that of pure Cu2O crystals.
Co-reporter:Xiong Zhang, Yuekun Lai, Mingzheng Ge, Yaxin Zheng, Ke-Qin Zhang and Zhiqun Lin
Journal of Materials Chemistry A 2015 - vol. 3(Issue 24) pp:NaN12768-12768
Publication Date(Web):2015/05/07
DOI:10.1039/C5TA03252K
A fibrous, flexible supercapacitor (FFSC) electrode with unique layer-by-layer structures is constructed using a one-step electrophoretic method. The highly enhanced capacitance of 53.56 mF cm−2 and good charge/discharge stability is attributed to the synergistic effect between the GO nano-sheet and carbon nano-sphere for electrolyte contact and ion transportation. Such a construction method can be employed to construct various FFSC electrodes for portable energy storage and wearable electronics applications.