Co-reporter:Yiqiang Sun, Bo Xu, Qi Shen, Lifeng Hang, Dandan Men, Tao Zhang, Huilin Li, Cuncheng Li, and Yue Li
ACS Applied Materials & Interfaces September 20, 2017 Volume 9(Issue 37) pp:31897-31897
Publication Date(Web):August 30, 2017
DOI:10.1021/acsami.7b09325
High-quality Au@ZnO core–shell nanoparticle (NP) array films were easily and efficiently fabricated through an air/water interfacial self-assembly. These materials have remarkable visible light absorption capacity and fascinating performance in photoelectrochemical (PEC) water splitting with a photocurrent density of ∼3.08 mA/cm2 at 0.4 V, which is superior to most ZnO-based photoelectrodes in studies. Additionally, the interesting PEC performance could be effectively adjusted by altering the thickness of the ZnO shell and/or the layer number of the array films. Results indicated that the bilayer film based on Au@ZnO NPs with 25 nm shell thickness displayed optimal behavior. The remarkable PEC capability could be ascribed to the enhanced light-harvesting ability of the Au@ZnO structured NPs by the SPR effect and the optimum film thickness. This work demonstrates a desirable paradigm for preparing photoelectrodes based on the synergistic effect of plasmatic NPs as the core and a visible optical absorbent and semiconductor as the shell. Moreover, this work provides a new approach for fabricating optoelectronic anode thin film devices through a self-assembly method.Keywords: Au@ZnO core−shell NPs nanoarrays; hydrogen generation; PEC water splitting; self-assembly;
Co-reporter:Tao Zhang;Fei Zhou;Lifeng Hang;Yiqiang Sun;Dilong Liu;Huilin Li;Guangqiang Liu;Xianjun Lyu;Cuncheng Li;Weiping Cai
Journal of Materials Chemistry C 2017 vol. 5(Issue 42) pp:11039-11045
Publication Date(Web):2017/11/02
DOI:10.1039/C7TC03855K
We develop an interesting route to prepare new sponge-like Au–Ag alloy nanocubes (NCs) with controlled porosity and atomic percentage through an interparticle alloying and dealloying process. Au@Ag NCs were first synthesized using Au nanooctahedra as initial seeds. Then, the Au@Ag NCs were covered with SiO2 and thermally annealed, forming solid Au–Ag alloy NCs with a SiO2 layer. After removing the majority of the SiO2 layer and leaching less-stable Ag from solid Au–Ag alloy NCs, uniform sponge-like porous Au–Ag alloy NCs were obtained. In this process, SiO2 not only prevents fusion between adjacent Au@Ag NPs under thermal annealing, but also directs the final shape of sponge-like Au–Ag alloy NPs with a cubic shape as a template. Thanks to the high-density “hotspots” in nanopores, sharp corners and edges, and a synergistic effect between Au and Ag species, such sponge-like Au–Ag alloy NCs showed excellent SERS performance with an enhancement factor of ∼108, which can effectively detect 4-aminothiophenol (4-ATP) at a concentration as low as 1 × 10−10 M. This strategy is universal and it can be extended to prepare sponge-like Au–Ag alloy NPs with different accurate shapes. Such sponge-like nanoporous alloy NPs have many potential applications such as in plasmonics, SERS, drug delivery, photothermal therapy, and catalysis systems.
Co-reporter:Dilong Liu;Cuncheng Li;Fei Zhou;Tao Zhang;Guangqiang Liu;Weiping Cai
Advanced Materials Interfaces 2017 Volume 4(Issue 10) pp:
Publication Date(Web):2017/05/01
DOI:10.1002/admi.201600976
A capillary gradient-induced self-assembly strategy is developed to successfully fabricate 2D periodic Au nanosphere arrays on a centimeter-sized scale through a bisolvent system at air/water interface. The bisolvent system used in this strategy consists of two steps. It first induces Au nanoparticles (NPs) floating on the water surface. Then, it compresses the sparse Au NPs into a densely close-packed array by creating an effective capillary gradient along the water surface. This study indicates that the effects of the capillary gradient depend on water solubility and vapor pressure of a compressing solvent. A compression mechanism of capillary gradient is reasonably proposed for such self-assembly of a densely packed monolayer on the water surface. This proposed self-assembly strategy has advantages of having a simple operation and being environment-friendly. The assembled Au NP arrays can provide an important and promising platform for major applications in biosensors and catalysis.
Co-reporter:Huilin Li, Dandan Men, Yiqiang Sun, Dilong Liu, Xinyang Li, Liangbin Li, Cuncheng Li, Weiping Cai, Yue Li
Journal of Colloid and Interface Science 2017 Volume 505(Volume 505) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.jcis.2017.06.034
We developed an interesting route for preparing a poly (acrylamide-co-acrylic acid) (P(AAm-co-AA)) hydrogel microsphere with a coating of Au nanospheres (hydrogel microsphere @ Au nanospheres) through self-assembly based on electrostatic interaction. The fabricated composites could be used as highly sensitive enhanced Raman scattering substrates. The nanogaps between adjacent Au nanospheres were dynamically tuned by volume changes in the hydrogel microspheres in the semiwet state under different pH conditions. At pH 6, the hydrogel microsphere @ Au nanospheres demonstrated highly sensitive SERS with an enhancement factor of 109. The product could detect very low concentrations of analytes up to 10−12 M 4-aminothiophenol (4-ATP) molecules. This paper proposes a new method for detecting trace amounts of environmental organic pollutants by dynamically tuning the SERS enhancement in the semiwet testing state.An interesting route was developed for preparing P(AAm-co-AA) hydrogel microsphere @ Au nanospheres through self-assembly based on electrostatic interaction. The nanogaps between adjacent Au nanospheres on the surfaces of P(AAm-co-AA) hydrogel microsphere could be tuned dynamically to obtain high SERS effect by controlling volume of the hydrogel microsphere under different pH condition in the semiwet state.Download high-res image (122KB)Download full-size image
Co-reporter:Yiqiang Sun;Lifeng Hang;Qi Shen;Tao Zhang;Huilin Li;Xiaomin Zhang;Xianjun Lyu
Nanoscale (2009-Present) 2017 vol. 9(Issue 43) pp:16674-16679
Publication Date(Web):2017/11/09
DOI:10.1039/C7NR03515B
We report the successful synthesis of Mo doped Ni2P nanowires (NWs) on a Ni foam (NF) substrate by a two-step strategy, which could be used as an efficient and stable hydrogen evolution reaction (HER) electrocatalyst over the whole pH range (0–14). Electrochemical investigations demonstrated that Mo doping made the catalytic activity of Ni2P significantly enhanced. To achieve a current density of 10 mA cm−2, Mo–Ni2P NWs/NF required an overpotential of 67 mV in acidic solution, 78 mV in alkaline solution and 84 mV in neutral solution. It also showed superior stability with negligible activity decay after its use in the HER under different pH conditions for 24 h. Such excellent HER activity might originate from the synergistic effect between molybdenum (Mo) and nickel (Ni) atoms. The present work provides a valuable route for the design and synthesis of inexpensive and efficient all-pH HER electrocatalysts.
Co-reporter:Lifeng Hang;Yiqiang Sun;Dandan Men;Shengwen Liu;Qian Zhao;Weiping Cai
Journal of Materials Chemistry A 2017 vol. 5(Issue 22) pp:11163-11170
Publication Date(Web):2017/06/06
DOI:10.1039/C7TA02539D
Hierarchical micro/nanostructured C doped Co/Co3O4 hollow spheres were prepared by two-step treatment (annealing at 600 °C in an Ar atmosphere and then at 250 °C in air) of PS@Co(OH)2 core–shell structures templated from PS microspheres without any modification. In 1 M KOH, such hollow nanospheres showed an overpotential of 352 mV at a benchmark oxygen evolution reaction (OER) current density of 10 mA cm−2, which was lower than that of RuO2 (364 mV), Co3O4 hollow nanospheres (410 mV) and C-Co/Co3O4 nanoparticles (462 mV). Importantly, the C-Co/Co3O4 hollow spheres exhibited a small onset potential (1.49 V) due to their more active sites, higher electrical conductivity, larger specific surface area, and excellent electron and ion diffusion permeability. This work provides a strategy to design and fabricate earth-abundant, low-cost electrocatalysts for water splitting in practical applications.
Co-reporter:Yiqiang Sun;Tao Zhang;Xinyang Li;Dilong Liu;Guangqiang Liu;Xiaomin Zhang;Xianjun Lyu;Weiping Cai
Chemical Communications 2017 vol. 53(Issue 99) pp:13237-13240
Publication Date(Web):2017/12/12
DOI:10.1039/C7CC07962A
We report the successful synthesis of Mn doped CoN nanowires on a carbon fiber cloth substrate (CFC) by a two-step strategy, which can be used as an efficient and stable OER electrocatalyst under both alkaline and neutral conditions. Benefiting from enhanced electronic interaction, high active area and electrical conductivity, the Mn doped CoN nanowires/CFC exhibits enhanced kinetics and improved cycling stability for the OER under both alkaline and neutral conditions. To achieve a current density of 10 mA cm−2, the Mn doped CoN nanowires/CFC requires an overpotential of 265 mV in alkaline solution and 285 mV in neutral solution.
Co-reporter:Dandan Men, Fei Zhou, Lifeng Hang, Xinyang Li, Guotao Duan, Weiping Cai and Yue Li
Journal of Materials Chemistry A 2016 vol. 4(Issue 11) pp:2117-2122
Publication Date(Web):23 Feb 2016
DOI:10.1039/C5TC04281J
Free-standing 2D Au nanosphere array/hydrogel composite sensing films were prepared by attaching a 2D Au nanosphere array onto a polyacrylic acid (PAAc) hydrogel film, which could be used as visualized sensors. These 2D Au nanosphere array/hydrogel composite films displayed visually diffraction color and much stronger diffraction intensity due to their periodic structures and large scattering cross-section of the Au nanospheres. Their diffraction intensity was increased by more than one order of magnitude (88 times) compared to that of 2D PS sphere array/hydrogel composite films to external stimuli, which is useful for visual observation by the naked eye and further optical characterization. Such 2D Au nanosphere array/hydrogel composite films exhibit ultrahigh diffraction intensity for them to be used for the visual determination of an analyte. The presented strategy could be extended to develop different visualized sensors based on various functional hydrogel films.
Co-reporter:Lifeng Hang, Yang Zhao, Honghua Zhang, Guangqiang Liu, Weiping Cai, Yue Li, Liangti Qu
Acta Materialia 2016 Volume 109() pp:405
Publication Date(Web):1 May 2016
DOI:10.1016/j.actamat.2016.01.045
Co-reporter:Lifeng Hang, Yang Zhao, Honghua Zhang, Guangqiang Liu, Weiping Cai, Yue Li, Liangti Qu
Acta Materialia 2016 Volume 105() pp:59-67
Publication Date(Web):15 February 2016
DOI:10.1016/j.actamat.2015.12.029
Abstract
Noble metal nanoparticles have been widely investigated for catalysis, while the source of noble metal is limited. Copper nanoparticles are the ideal candidates for replacing noble metal nanoparticles in the specific catalysis field. However, Cu NPs from traditional methods are generally nonuniform in morphology and wide distribution in size. In this work, a simple method is developed to fabricate uniform copper nanosphere arrays on a large scale (∼cm2) using monolayer colloidal crystals as templates. A reduced graphene oxide (rGO) is further introduced on the surfaces of Cu nanospheres to form the Cu NPs@rGO core–shell structured arrays on the substrates by the redox reaction. The rGO shell can protect the Cu NPs from oxidation, which guarantees the good stability of Cu@rGO nanoparticle arrays. The obtained Cu@rGO core–shell arrays (periodic length: 350 nm, diameter: 110 nm) exhibit excellent catalytic performance towards the reduction of 4-nitrophenol to 4-aminophenol, which is 14 times larger than that of Au nanoparticles as previously reported. With decreasing the length of periodicity of Cu@rGO core–shell array, its catalytic activity increases. When the periodicity is fixed, with increase of Cu NP size, the value of activity factor k is decreasing. More importantly, such Cu@rGO core–shell arrays on the supporting substrates can be easily recycled for the catalytic reaction. These Cu@rGO arrays have also other potential applications in SERS, electrochemistry, biosensor, etc.
Co-reporter:Dandan Men;Dilong Liu
Science Bulletin 2016 Volume 61( Issue 17) pp:1358-1371
Publication Date(Web):2016 September
DOI:10.1007/s11434-016-1134-7
Responsive photonic crystals (RPCs) constructed by periodic two/three-dimensional (2D/3D) photonic crystals (PCs) and responsive-material hosts, are important visualized optical sensors. Their optical diffraction color can be tuned reversibly by external stimuli, such as pH, metal ions, biomolecules, vapors and solvents, hence leading to wide applications as visualized sensors. This review introduces the recent progress of RPCs based on 2D/3D PCs for visual detection of chemical and biological analytes, including the preparation of 2D PCs, 3D PCs films, 3D PCs microbeads and their applications as visualized sensors. The different cases of detecting various chemical and biological analytes by naked eyes are presented. Emphasis is given to the description of their respective sensing mechanisms with the different systems for chemical and biological analytes. Compared with 3D RPCs sensors, 2D RPCs sensors have shorter response time, better stabilization and higher production efficiency, however, the diffraction intensity of 2D RPCs based on monolayered 2D polystyrene (PS) microsphere array are weak. 2D RPCs sensors based on 2D Au nanosphere can significantly improve the diffraction intensity compared with traditional 2D RPCs sensors based on monolayered PS microsphere array. The much higher scattering cross section of Au nanosphere leads to 2D Au nanosphere array with ultrahigh optical diffraction intensity, which are highly helpful for their practical application as visual sensors and further quantitative detection by monitoring the diffraction peak position and intensity.基于二维和三维响应光子晶体,可构筑可视化传感器,其宏观颜色可以通过外界刺激,例如pH值、离子强度、生物分子、气体和溶剂等进行调节,从而实现根据宏观颜色的变化对外界刺激进行可视化探测。本文介绍了二维和三维响应光子晶体作为可视化传感器的研究进展,包括:三维光子晶体珠、三维光子晶体薄膜和二维光子晶体的制备;响应光子晶体的设计;光子晶体在生化物质探测方面的应用及其敏感机理。与三维响应光子晶体相比,二维响应光子晶体具有制备简单、稳定性好、响应时间快的优势,但是衍射信号弱。相比于负载单层二维聚苯乙烯微球阵列的二维响应光子晶体,基于负载单层二维金纳米球阵列的二维响应光子晶体可以大幅度提高衍射光的强度,其超高的衍射光强度有助于推进二维响应光子晶体作为可视化传感器在实际中的应用。
Co-reporter:Dandan Men, Honghua Zhang, Lifeng Hang, Dilong Liu, Xinyang Li, Weiping Cai, Qihua Xiong and Yue Li
Journal of Materials Chemistry A 2015 vol. 3(Issue 15) pp:3659-3665
Publication Date(Web):13 Feb 2015
DOI:10.1039/C5TC00174A
An interesting strategy to create free standing hydrogel composite films with colloidal monolayers attached on both the surfaces, which could act as visualizing sensors with high diffraction intensity, is developed. Owing to the balanced stress on both the surfaces, the colloidal monolayer–hydrogel composite films overcome the curling problem of traditional hydrogel films loaded with a colloidal monolayer on one side. They also display enhanced diffraction intensity compared to those with the attachment of only a single 2D colloidal monolayer due to a multi-diffraction effect. Such sensing hydrogel composite films with anti-curling performance and enhanced optical diffraction intensity are very helpful to improve their practical applications in visual and quantitative detection. In addition, this strategy is universal and could be suitable for fabricating various functional hydrogel films loaded with different nanosphere arrays for novel optical sensors.
Co-reporter:Xinyang Li, Yanchun Wu, Lifeng Hang, Dandan Men, Weiping Cai and Yue Li
Journal of Materials Chemistry A 2015 vol. 3(Issue 1) pp:51-57
Publication Date(Web):11 Nov 2014
DOI:10.1039/C4TC02228A
A simple, low-cost and high-throughput technique to fabricate aligned Au nanobowl arrays is presented by combining template-assisted self-assembly and colloidal lithography. Polystyrene (PS) colloids were self-assembled into the aligned grooves on a blank digital versatile disc (DVD) substrate, forming aligned PS colloidal necklace arrays. After being coated with an Au layer, they were inverted onto another glass slide with a polyvinyl alcohol (PVA) thin layer and aligned Au nanobowl arrays were obtained after peeling off the DVD substrate and removing the PS colloidal spheres. If the glass slide substrate was removed, the aligned Au nanobowl arrays on a flexible PVA substrate could be achieved. These Au nanobowl alignments displayed higher reflectance and could be used as an optical grating. They also demonstrated anisotropic optical properties and have important potential applications in optical devices, such as optical gratings, waveguide, and so on. This work will provide new insights and understanding of the control of morphology and enhancement of optical properties of Au nanoparticle arrays and it is helpful to develop new optical devices based on such anisotropic optical performance.
Co-reporter:Honghua Zhang;Fei Zhou;Mao Liu;Dilong Liu;Dan Men;Weiping Cai;Guotao Duan
Advanced Materials Interfaces 2015 Volume 2( Issue 9) pp:
Publication Date(Web):
DOI:10.1002/admi.201500031
Periodic hexagonal spherical nanoparticle arrays are fabricated by a sacrificial colloidal monolayer template route by chemical deposition and further physical deposition. The regular network-structured arrays are first templated by colloidal monolayers and then they are changed to novel periodic spherical nanoparticle arrays by further sputtering deposition due to multiple direction deposition and shadow effect between adjacent nanoparticles. The nanogaps between two adjacent spherical nanoparticles can be well tuned by controlling deposition time. Such periodic nanoparticle arrays with gold coatings demonstrate a very stable and high sensitive surface-enhanced Raman scattering spectroscopy (SERS) performance. The periodic nanoparticle arrays with 10 nm gaps display much stronger SERS enhancement due to electromagnetic coupling. The chemically modified nanoparticle arrays show good hydrophobicity, which shorten process of detecting probe molecules using them as SERS-active substrates by localized concentration of droplet evaporation and a low detection limit of 10−12 m R6G can be achieved without solution wasting in a short time. The hydrophobic substrate offers a simple, convenient, and economical method to examine SERS performance by rapid concentration of solution on it and it is highly helpful to improve its practical applications in portable Raman detecting devices to detect organic molecules.
Co-reporter:Zhengfei Dai;Hui Dai;Yong Zhou;Dilong Liu;Guotao Duan;Weiping Cai
Advanced Materials Interfaces 2015 Volume 2( Issue 11) pp:
Publication Date(Web):
DOI:10.1002/admi.201500167
Co-reporter:Hongwen Zhang, Yue Li, Guotao Duan, Guangqiang Liu and Weiping Cai
CrystEngComm 2014 vol. 16(Issue 12) pp:2491-2498
Publication Date(Web):17 Jan 2014
DOI:10.1039/C3CE42320D
A facile and chemically clean method is presented to fabricate the nanostructured tungsten oxide (WO3) based on laser ablation of a tungsten flake in water and a subsequent hydrothermal route. The typically nanostructured WO3 objects were well-dispersed and brick-like in shape. The bricks have average dimensions of ca. 200 nm in length, 150 nm in width and 130 nm in thickness, with stepped structures on their planar surfaces. Further experiments revealed that the reaction temperature, pH value and composition of the precursor in the subsequent hydrothermal treatment are crucial to formation of the brick-like WO3 nanostructures. Correspondingly, a rectangular cuboidal stacking growth model is proposed to describe the formation of such nanobricks. The nanobricks could be good building blocks of complex micro/nanostructures and devices. Also, the combination of laser ablation in liquid with hydrothermal treatment could provide an effective synthetic approach for morphologically tunable WO3 nanomaterials, which have potential applications in gas sensing, electrochromic devices and photocatalysis.
Co-reporter:Lifeng Hang, Cuncheng Li, Tao Zhang, Xinyang Li, Yanchun Wu, Dandan Men, Guangqiang Liu and Yue Li
RSC Advances 2014 vol. 4(Issue 110) pp:64668-64674
Publication Date(Web):18 Nov 2014
DOI:10.1039/C4RA09557J
A modified polyol process is a convenient route to prepare monodispersed, uniform spherical Au nanospheres stabilized by Poly Diallyl Dimethyl Ammonium Chloride (PDDA). However, Au nanospheres with PDDA coatings possess a high zeta potential and such PDDA coatings can not be removed easily, leading to a difficulty in coating a silica layer on surfaces of Au nanospheres, further resulting in the limitation of the applications of these monodispersed Au nanoparticles (NPs). Herein, we develop a novel route to coat a silica layer on PDDA stabilized Au nanospheres assisted by UV light irradiation without the use of a silane coupling agent as the surface primer. PDDA-stabilized Au nanospheres showed high a positive zeta potential (36.7 mV), which is disadvantageous to coat a layer of thin silica shell. In our strategy, UV light irradiation with high power was applied to PDDA stabilized Au nanoparticles and part of PDDA on Au nanoparticles was degradated, producing lower positive zeta potential (14.7 mV), which guaranteed that silica shell could be easily formed on the surface of Au sphere under such a low zeta potential. The thickness of silica shell could be successfully tuned from 2 nm to 8 nm by adjusting the concentration of TEOS. As far as we know, this is first report to coat the silica layer on PDDA stabilized Au nanospheres. Such monodispersed Au spherical nanoparticles with controlled silica coatings could be extended to important applications in SERS applications, electrochemistry after self-assembled into monolayer particle arrays.
Co-reporter:Yue Li, Guotao Duan, Guangqiang Liu and Weiping Cai
Chemical Society Reviews 2013 vol. 42(Issue 8) pp:3614-3627
Publication Date(Web):12 Feb 2013
DOI:10.1039/C3CS35482B
It has been proven that the use of colloidal templates is a facile, flexible strategy to create the periodic micro/nanostructured arrays in comparison with photolithography, electron beam lithography etc. Utilizing colloidal monolayers as templates or masks, different periodic micro/nanostructured arrays including nanoparticle arrays, pore arrays, nanoring arrays and nanorod/nanotube arrays can be fabricated by chemical and physical processes. Chemical routes, including direct solution/sol dipping strategy, wet chemical etching, electrodeposition, electrophoretic deposition etc. have advantages of simple operation and low costs. However, they have some disadvantages of impurities on surface of arrays due to incomplete decomposition of precursors, residue of surfactants in self-assembling or electrochemical deposition. More importantly, it is quite difficult to achieve very uniform morphology of micro/nanostructure arrays on a large-area by the above routes. Whereas another method, a physical route (for instance: reactive ion etching, pulsed laser deposition, thermal evaporation deposition, atomic layer deposition, sputtering deposition), combining with colloidal monolayer template can well resolve these problems. In this review, we focus on introducing the recent progress in creating micro/nanostructured arrays based on colloidal templates with physical routes. The parameters of the microstructure or nanostructure can be tuned by colloidal templates with different periodicity and experimental conditions of the physical processes. The applications of micro/nanostructured arrays with controllable morphology and arrangement parameters in self-cleaning surfaces, enhanced catalytic properties, field emitters etc. are also presented in the following sections.
Co-reporter:Zhigang Li, Li Zhang, Qintao Li, Jinlian Hu, Peisheng Liu, Shangshen Feng, Weiping Chen and Yue Li
RSC Advances 2013 vol. 3(Issue 34) pp:14829-14836
Publication Date(Web):07 Jun 2013
DOI:10.1039/C3RA41931B
A strategy is proposed for the synthesis of heterogeneous/homogeneous binary arrays via stepwise colloidal lithography, using ZnO and Ni as model materials. A series of controllable and specific binary arrays like pore/pillar, pore/pore, ring/triangle nanoparticle and ring/pore were designed and then fabricated. The periodicity of the binary array can be tuned by the size of the polystyrene spheres, the size and structure of each unit in the array can be selectively controlled by proper heat treatment, and the distance between the adjacent units of two arrays can be manipulated by the incidence angle of metal vapor flow. This study gives an effective guide to designing desired patterns of heterogeneous/homogeneous binary arrays and accurately determining their size and structure. Furthermore, this strategy allows two materials with different properties, such as magnetic, photonic, catalytic and semiconducting, to be assembled in one array with tunable arrangements, with potential applications in multi-function nanodevices.
Co-reporter:Dr. Zhengfei Dai;Dr. Lichao Jia;Dr. Guotao Duan; Yue Li;Dr. Hongwen Zhang;Jingjing Wang; Jinlian Hu; Weiping Cai
Chemistry - A European Journal 2013 Volume 19( Issue 40) pp:13387-13395
Publication Date(Web):
DOI:10.1002/chem.201301137
Abstract
Homogenous thin films are preferable for high-performance gas sensors because of their remarkable reproducibility and long-term stability. In this work, a low-temperature fabrication route is presented to prepare crack-free and homogenous metal oxide periodic porous thin films by oxygen plasma irradiation instead of high temperature annealing by using a sacrificial colloidal template. Rutile SnO2 is taken as an example to demonstrate the validity of this route. The crack-free and homogenous porous thin films are successfully synthesized on the substrates in situ with electrodes. The SnO2 porous thin film obtained by plasma irradiation is rich in surface OH groups and hence superhydrophilic. It exhibits a more homogenous structure and lower resistance than porous films generated by annealing. More importantly, such thin films display higher sensitivity, a lower detection threshold (100 ppb to acetone) and better durability than those that have been directly annealed, resulting in enhanced gas-sensing performance. The presented method could be applied to synthesize other metal oxide homogenous thin films and to fabricate gas-sensing devices with high performances.
Co-reporter:Dr. Zhengfei Dai;Dr. Lichao Jia;Dr. Guotao Duan; Yue Li;Dr. Hongwen Zhang;Jingjing Wang; Jinlian Hu; Weiping Cai
Chemistry - A European Journal 2013 Volume 19( Issue 40) pp:
Publication Date(Web):
DOI:10.1002/chem.201390155
Co-reporter:Hongwen Zhang, Guotao Duan, Yue Li, Xiaoxia Xu, Zhengfei Dai, and Weiping Cai
Crystal Growth & Design 2012 Volume 12(Issue 5) pp:2646-2652
Publication Date(Web):April 15, 2012
DOI:10.1021/cg300226r
A facile and chemically clean method, pulsed laser ablation in liquid medium (LAL), was utilized to produce precursor solutions, and leaf-like tungsten oxide (WO3) nanoplatelets were synthesized after sequential aging treatment of precursors. In this work, the effects of aging temperature, aging time, and pH value of precursor solutions have been investigated. The well-defined leaf-like WO3 nanoplatelets can only be achieved by aging the pristine precursor solutions at room temperature (25 °C) for 48 h. In particular, when the pH value of precursor solutions was decreased lower than 1.0, the obtained products were hierarchical quasi-spheres composed of several nanoplates. The preparation method reported here shows a novel synthetic approach to control and adjust the morphology and crystallite size of the prepared WO3 nanomaterials, which has potential applications in gas sensing, electrochromic devices, and photocatalysis.
Co-reporter:Zhengfei Dai, Yue Li, Guotao Duan, Lichao Jia, and Weiping Cai
ACS Nano 2012 Volume 6(Issue 8) pp:6706
Publication Date(Web):July 30, 2012
DOI:10.1021/nn3013178
Flexible structural design and accurate controlled fabrication with structural tunability according to need for binary or multicomponent colloidal crystals have been expected. However, it is still a challenge. In this work, the phase diagram of monolayer binary colloidal crystals (bCCs) is established on the assumption that both large and small polystyrene (PS) colloidal spheres can stay at the air/water interface, and the range diagram for the size ratio and number ratio of small to large colloidal spheres is presented. From this phase diagram, combining the range diagram, we can design and relatively accurately control fabrication of the bCCs with specific structures (or patterns) according to need, including single or mixed patterns with the given relative content. Further, a simple and facile approach is presented to fabricate large-area (more than 10 cm2) monolayer bCCs without any surfactants, using differently sized PS spheres, based on ethanol-assisted self-assembly at the air/water interface. bCCs with different patterns and stoichiometries are thus designed from the established phase diagram and then successfully fabricated based on the volume ratios (VS/L) of the small to large PS suspensions using the presented colloidal self-assembling method. Interestingly, these monolayer bCCs can be transferred to any desired substrates using water as the medium. This study allows us to design desired patterns of monolayer bCCs and to more accurately control their structures with the used VS/L.Keywords: air/water interface; ethanol-assisted self-assembly; monolayer binary colloidal crystals; pattern design; phase diagram
Co-reporter:Yue Li, Naoto Koshizaki, Hongqiang Wang, and Yoshiki Shimizu
ACS Nano 2011 Volume 5(Issue 12) pp:9403
Publication Date(Web):October 29, 2011
DOI:10.1021/nn203239n
A unique approach for fabricating complex hierarchical periodic arrays with trinary stepwise architectures of micro- and submicro- as well as nanosized structures by combining a novel double-layered binary colloidal crystal with pulsed laser deposition techniques is developed. The present strategy is universal and nanostructures with different materials can be easily prepared in the complex hierarchical periodic arrays. This approach offers the advantage of low costs compared to conventional lithographic techniques. These as-prepared unique structures cannot be directly fabricated by conventional lithography. These special hierarchically structured arrays demonstrate fine structure-enhanced performances, including superhydrophilicity without UV irradiation and surface enhanced Raman scattering (SERS), which is highly valuable for designing micro/nanodevices, such as biosensors or microfluidic devices.Keywords: binary colloidal crystals; enhanced properties; hierarchical array; trinary
Co-reporter:Shuyan Gao, Zhengdao Li, Shuxia Yang, Kai Jiang, Yue Li, Haibo Zeng, Liang Li and Hongqiang Wang
ACS Applied Materials & Interfaces 2009 Volume 1(Issue 9) pp:2080
Publication Date(Web):September 15, 2009
DOI:10.1021/am900466f
A new route combining a facile wet-chemical process and spin coating was developed to fabricate a CuI film assembled by hexagonal crystals. Remarkably, such a CuI film displays excellent superhydrophobicity without further modification by low-free-energy materials (thiol or fluoroalkylsilane). The special wettability is attributed to a hierarchical morphology of CuI crystals with two length-scale roughnesses and the nature of the material itself. Importantly, this superhydrophobicity is quite stable and the water contact angle of the as-prepared sample only decreases slightly, even when it is kept in air for about half a year. The superhydrophobicity of the as-prepared CuI powder is a bulk property of the material and not just of its surface, so such a powder coating could then prove useful in conferring superhydrophobicity to other surfaces to which it is applied. These facts might improve its practical application with environmental friendship in superhydrophobic coatings.Keywords: hexagonal CuI powder; low-free-energy materials; modification; transferrable superhydrophobic surface
Co-reporter:Yue Li, Naoto Koshizaki, Yoshiki Shimizu, Liang Li, Shuyan Gao and Takeshi Sasaki
ACS Applied Materials & Interfaces 2009 Volume 1(Issue 11) pp:2580
Publication Date(Web):October 28, 2009
DOI:10.1021/am900513m
We have developed a strategy for designing and fabricating hierarchical micro-/nanostructured arrays based on the combination of a colloidal monolayer substrate and the pulsed laser deposition (PLD) process. In this approach, microstructures are provided by the colloidal monolayer and can be tuned by changing colloidal monolayer periodicities, while crystalline nanostructures are supplied by PLD and can be controlled by PLD experiment parameters (e.g., ambient gas pressure). In comparison with the traditional lithography techniques, the proposed method has the obvious advantage of low cost. More importantly, the complicated hierarchical micro-/nanostructure arrays obtained by the present strategy cannot easily be designed and synthesized by traditional lithography techniques. This fact suggests that the proposed method can be a quite powerful alternative to fabricate complicated hierarchical arrays by complementing the weakness of traditional lithographic routes. In addition to these, the strategy also features uniform surface morphology, room-temperature reaction, and pure sample surfaces that are highly valuable to build a new generation of microdevices or nanodevices in nanophotonics, energy storage, etc. on the basis of these special hierarchical micro-/nanostructured arrays.Keywords: aligned; hierarchical; micro-/nanostructure arrays; one-dimensional nanostructures; room temperature
Co-reporter:Yue Li, Weiping Cai and Guotao Duan
Chemistry of Materials 2008 Volume 20(Issue 3) pp:615
Publication Date(Web):November 8, 2007
DOI:10.1021/cm701977g
Besides the traditional lithographical techniques to fabricate the ordered mciro/nanostructured arrays, the route of the monolayer colloidal crystal template is a recently promising, alternative process for the synthesis of the micro/nanostructures with different designed morphologies. By this strategy, two-dimensional ordered arrays, e.g., nanoparticle arrays, pore arrays, nanoring arrays, nanobowl arrays, hollow sphere arrays, etc., even one-dimensional nanostructures of ordered nanorod/nanopillar/nanowire arrays, etc., could be prepared. Recent progress in this area is reviewed, including synthesis strategies and morphology-dependent properties of the micro/nanostructured arrays such as optical properties, wettability, surface-enhanced Raman scattering, and photonic bandgap.
Co-reporter:
Science 1911 Vol 34(868) pp:218-224
Publication Date(Web):18 Aug 1911
DOI:10.1126/science.34.868.218
Co-reporter:Dandan Men, Dilong Liu, Yue Li
Science Bulletin (September 2016) Volume 61(Issue 17) pp:1358-1371
Publication Date(Web):1 September 2016
DOI:10.1007/s11434-016-1134-7
Responsive photonic crystals (RPCs) constructed by periodic two/three-dimensional (2D/3D) photonic crystals (PCs) and responsive-material hosts, are important visualized optical sensors. Their optical diffraction color can be tuned reversibly by external stimuli, such as pH, metal ions, biomolecules, vapors and solvents, hence leading to wide applications as visualized sensors. This review introduces the recent progress of RPCs based on 2D/3D PCs for visual detection of chemical and biological analytes, including the preparation of 2D PCs, 3D PCs films, 3D PCs microbeads and their applications as visualized sensors. The different cases of detecting various chemical and biological analytes by naked eyes are presented. Emphasis is given to the description of their respective sensing mechanisms with the different systems for chemical and biological analytes. Compared with 3D RPCs sensors, 2D RPCs sensors have shorter response time, better stabilization and higher production efficiency, however, the diffraction intensity of 2D RPCs based on monolayered 2D polystyrene (PS) microsphere array are weak. 2D RPCs sensors based on 2D Au nanosphere can significantly improve the diffraction intensity compared with traditional 2D RPCs sensors based on monolayered PS microsphere array. The much higher scattering cross section of Au nanosphere leads to 2D Au nanosphere array with ultrahigh optical diffraction intensity, which are highly helpful for their practical application as visual sensors and further quantitative detection by monitoring the diffraction peak position and intensity.
Co-reporter:Lifeng Hang, Yiqiang Sun, Dandan Men, Shengwen Liu, Qian Zhao, Weiping Cai and Yue Li
Journal of Materials Chemistry A 2017 - vol. 5(Issue 22) pp:NaN11170-11170
Publication Date(Web):2017/05/05
DOI:10.1039/C7TA02539D
Hierarchical micro/nanostructured C doped Co/Co3O4 hollow spheres were prepared by two-step treatment (annealing at 600 °C in an Ar atmosphere and then at 250 °C in air) of PS@Co(OH)2 core–shell structures templated from PS microspheres without any modification. In 1 M KOH, such hollow nanospheres showed an overpotential of 352 mV at a benchmark oxygen evolution reaction (OER) current density of 10 mA cm−2, which was lower than that of RuO2 (364 mV), Co3O4 hollow nanospheres (410 mV) and C-Co/Co3O4 nanoparticles (462 mV). Importantly, the C-Co/Co3O4 hollow spheres exhibited a small onset potential (1.49 V) due to their more active sites, higher electrical conductivity, larger specific surface area, and excellent electron and ion diffusion permeability. This work provides a strategy to design and fabricate earth-abundant, low-cost electrocatalysts for water splitting in practical applications.
Co-reporter:Yiqiang Sun, Lifeng Hang, Dandan Men, Huilin Li, Dilong Liu, Xinyang Li, Lulu Wen and Yue Li
Journal of Materials Chemistry A 2016 - vol. 4(Issue 41) pp:NaN9871-9871
Publication Date(Web):2016/09/27
DOI:10.1039/C6TC03657K
Periodic gold nanosphere arrays were prepared on a planar silicon substrate, which could be directly developed as an electrode to sensitively and selectively detect H2O2 without an enzyme via an electrochemical method. The arrays of Au nanospheres were fabricated on a large scale (∼cm2) on the Si substrate using polystyrene (PS) colloidal monolayers as the template, after Au deposition and subsequent annealing. The developed biosensor based on the Au nanosphere arrays on the Si substrate demonstrated excellent catalytic activity towards H2O2 over a wide linear range of 0.2 μM–5 mM with a very low detection limit of 0.1 μM. Importantly, the electrochemical biosensor possessed good stability and high reproducibility. The catalytic activity can be enhanced by reducing the gold nanoparticle size and periodic length in the array. The biosensors based on periodic Au nanosphere arrays used to determine the concentration of H2O2 have the advantages of non-enzymatic detection and non-Pt electrode strategy when compared to the conventional method, which may open up new horizons in the production of outstanding biosensors and can be used as a platform for the preparation of various electrochemical biosensors.
Co-reporter:Dandan Men, Honghua Zhang, Lifeng Hang, Dilong Liu, Xinyang Li, Weiping Cai, Qihua Xiong and Yue Li
Journal of Materials Chemistry A 2015 - vol. 3(Issue 15) pp:NaN3665-3665
Publication Date(Web):2015/02/13
DOI:10.1039/C5TC00174A
An interesting strategy to create free standing hydrogel composite films with colloidal monolayers attached on both the surfaces, which could act as visualizing sensors with high diffraction intensity, is developed. Owing to the balanced stress on both the surfaces, the colloidal monolayer–hydrogel composite films overcome the curling problem of traditional hydrogel films loaded with a colloidal monolayer on one side. They also display enhanced diffraction intensity compared to those with the attachment of only a single 2D colloidal monolayer due to a multi-diffraction effect. Such sensing hydrogel composite films with anti-curling performance and enhanced optical diffraction intensity are very helpful to improve their practical applications in visual and quantitative detection. In addition, this strategy is universal and could be suitable for fabricating various functional hydrogel films loaded with different nanosphere arrays for novel optical sensors.
Co-reporter:Xinyang Li, Yanchun Wu, Lifeng Hang, Dandan Men, Weiping Cai and Yue Li
Journal of Materials Chemistry A 2015 - vol. 3(Issue 1) pp:NaN57-57
Publication Date(Web):2014/11/11
DOI:10.1039/C4TC02228A
A simple, low-cost and high-throughput technique to fabricate aligned Au nanobowl arrays is presented by combining template-assisted self-assembly and colloidal lithography. Polystyrene (PS) colloids were self-assembled into the aligned grooves on a blank digital versatile disc (DVD) substrate, forming aligned PS colloidal necklace arrays. After being coated with an Au layer, they were inverted onto another glass slide with a polyvinyl alcohol (PVA) thin layer and aligned Au nanobowl arrays were obtained after peeling off the DVD substrate and removing the PS colloidal spheres. If the glass slide substrate was removed, the aligned Au nanobowl arrays on a flexible PVA substrate could be achieved. These Au nanobowl alignments displayed higher reflectance and could be used as an optical grating. They also demonstrated anisotropic optical properties and have important potential applications in optical devices, such as optical gratings, waveguide, and so on. This work will provide new insights and understanding of the control of morphology and enhancement of optical properties of Au nanoparticle arrays and it is helpful to develop new optical devices based on such anisotropic optical performance.
Co-reporter:Dandan Men, Fei Zhou, Lifeng Hang, Xinyang Li, Guotao Duan, Weiping Cai and Yue Li
Journal of Materials Chemistry A 2016 - vol. 4(Issue 11) pp:NaN2122-2122
Publication Date(Web):2016/02/23
DOI:10.1039/C5TC04281J
Free-standing 2D Au nanosphere array/hydrogel composite sensing films were prepared by attaching a 2D Au nanosphere array onto a polyacrylic acid (PAAc) hydrogel film, which could be used as visualized sensors. These 2D Au nanosphere array/hydrogel composite films displayed visually diffraction color and much stronger diffraction intensity due to their periodic structures and large scattering cross-section of the Au nanospheres. Their diffraction intensity was increased by more than one order of magnitude (88 times) compared to that of 2D PS sphere array/hydrogel composite films to external stimuli, which is useful for visual observation by the naked eye and further optical characterization. Such 2D Au nanosphere array/hydrogel composite films exhibit ultrahigh diffraction intensity for them to be used for the visual determination of an analyte. The presented strategy could be extended to develop different visualized sensors based on various functional hydrogel films.
Co-reporter:Yue Li, Guotao Duan, Guangqiang Liu and Weiping Cai
Chemical Society Reviews 2013 - vol. 42(Issue 8) pp:NaN3627-3627
Publication Date(Web):2013/02/12
DOI:10.1039/C3CS35482B
It has been proven that the use of colloidal templates is a facile, flexible strategy to create the periodic micro/nanostructured arrays in comparison with photolithography, electron beam lithography etc. Utilizing colloidal monolayers as templates or masks, different periodic micro/nanostructured arrays including nanoparticle arrays, pore arrays, nanoring arrays and nanorod/nanotube arrays can be fabricated by chemical and physical processes. Chemical routes, including direct solution/sol dipping strategy, wet chemical etching, electrodeposition, electrophoretic deposition etc. have advantages of simple operation and low costs. However, they have some disadvantages of impurities on surface of arrays due to incomplete decomposition of precursors, residue of surfactants in self-assembling or electrochemical deposition. More importantly, it is quite difficult to achieve very uniform morphology of micro/nanostructure arrays on a large-area by the above routes. Whereas another method, a physical route (for instance: reactive ion etching, pulsed laser deposition, thermal evaporation deposition, atomic layer deposition, sputtering deposition), combining with colloidal monolayer template can well resolve these problems. In this review, we focus on introducing the recent progress in creating micro/nanostructured arrays based on colloidal templates with physical routes. The parameters of the microstructure or nanostructure can be tuned by colloidal templates with different periodicity and experimental conditions of the physical processes. The applications of micro/nanostructured arrays with controllable morphology and arrangement parameters in self-cleaning surfaces, enhanced catalytic properties, field emitters etc. are also presented in the following sections.
