Co-reporter:Long Wang, Yishi Wu, Jianwei Chen, Lanfen Wang, Yanping Liu, Zhenyi Yu, Jiannian Yao, and Hongbing Fu
The Journal of Physical Chemistry Letters November 16, 2017 Volume 8(Issue 22) pp:5609-5609
Publication Date(Web):October 31, 2017
DOI:10.1021/acs.jpclett.7b02597
A new class of donor–acceptor heterodimers based on two singlet fission (SF)-active chromophores, i.e., pentacene (Pc) and perylenediimide (PDI), was developed to investigate the role of charge transfer (CT) state on the excitonic dynamics. The CT state is efficiently generated upon photoexcitation. However, the resulting CT state decays to different energy states depending on the energy levels of the CT state. It undergoes extremely rapid deactivation to the ground state in polar CH2Cl2, whereas it undergoes transformation to a Pc triplet in nonpolar toluene. The efficient triplet generation in toluene is not due to SF but CT-mediated intersystem crossing. In light of the energy landscape, it is suggested that the deep energy level of the CT state relative to that of the triplet pair state makes the CT state actually serve as a trap state that cannot undergoes an intramolecular singlet fission process. These results provide guidance for the design of SF materials and highlight the requisite for more widely applicable design principles.
Co-reporter:Lu Xiao, Yishi Wu, Jianwei Chen, Zhenyi Yu, Yanping Liu, Jiannian Yao, and Hongbing Fu
The Journal of Physical Chemistry A November 16, 2017 Volume 121(Issue 45) pp:8652-8652
Publication Date(Web):October 24, 2017
DOI:10.1021/acs.jpca.7b10160
The development of metal-free organic room temperature phosphorescence (RTP) materials has attracted increasing attention because of their applications in sensors, biolabeling (imaging) agents and anticounterfeiting technology, but remains extremely challenging owing to the restricted spin-flip intersystem crossing (ISC) followed by low-yield phosphorescence that cannot compete with nonradiative relaxation processes. Here, we report a facile strategy to realize highly efficient RTP by doping iodo difluoroboron dibenzoylmethane (I-BF2dbm-R) derivatives into a rigid crystalline 4-iodobenzonitrile (Iph-C≡N) matrix. We found that halogen bonding between cyano group of Iph-C≡N matrix and iodine atom of I-BF2dbm-R dopant is formed in doped crystals, i.e., Iph-C≡N···I-BF2dbm-R, which not only suppresses nonradiative relaxation of triplets but also promotes the spin–orbit coupling (SOC). As a result, the doped crystals show intense RTP with an efficiency up to 62.3%. By varying the substituent group R in I-BF2dbm-R from electron donating −OCH3 to electron accepting −F, −CN groups, the ratio between phosphorescence and fluorescence intensities has been systematically increased from 3.8, 15, to 50.
Co-reporter:Jinbiao Li;Yishi Wu;Zhenzhen Xu;Qing Liao;Haihua Zhang;Yi Zhang;Lu Xiao;Jiannian Yao
Journal of Materials Chemistry C 2017 vol. 5(Issue 46) pp:12235-12240
Publication Date(Web):2017/11/30
DOI:10.1039/C7TC04207H
The excited-state intramolecular proton transfer (ESIPT) process provides a real four-level system, which forms the working basis of many laser dyes in solutions but remains largely unexplored in the solid-state gain medium. Herein, we modulated the keto* and enol* emissions by switching the intramolecular hydrogen-bond to the intermolecular hydrogen-bond in the solid-state for tuning the emission colors of ESIPT-microcrystal lasers. Both model compounds of 2′-hydroxychalcone derivatives of M1 and M2 exhibit very similar dual enol* and keto* emissions in the aprotic solvents, typical for ESIPT-active molecules. When aggregated into hexagonal-plate microcrystals (HPMCs), the intramolecular hydrogen-bond ensures the photoinduced proton tautomerization from enol* to keto* tautomers, resulting in intense red fluorescence of M1 HPMCs at 647 nm from the keto* form. In sharp contrast, the introduction of an extra hydroxyl group into M2 leads to the formation of an intermolecular hydrogen bond between two adjacent molecules, which suppresses the ESIPT process in the solid-state and therefore leads to intense green emission of M2 HPMCs at 537 nm from the enol* form. The solid-state photoluminescence efficiencies of HPMCs of M1 and M2 are as high as 42% and 51%, respectively. Moreover, well-faceted HPMCs of both M1 and M2 can function as whispering-gallery mode microresonators, enabling microlasers with very low laser thresholds of 10.8 μJ cm−2 for red-emissive M1-HPMCs and 9.4 μJ cm−2 for green emissive M2-HPMCs.
Co-reporter:Zilong Wang;Peiyang Gu;Guangfeng Liu;Huiying Yao;Yishi Wu;Yongxin Li;Ganguly Rakesh;Jia Zhu;Qichun Zhang
Chemical Communications 2017 vol. 53(Issue 55) pp:7772-7775
Publication Date(Web):2017/07/06
DOI:10.1039/C7CC03898D
Here, we present our recent progress on the synthesis, crystal structure, physical properties and DFT calculations of a novel large pyrene-fused N-heteroacene (15RINGS) with 15 aromatic six-membered rings linearly fused in one row. The long conjugated backbone (more than 35 Å) of 15RINGS possesses a dual-bending feature (the bending angle is about 13.2°).
Co-reporter:Chun-Lin Sun;Shao-Kai Lv;Yan-Ping Liu;Qing Liao;Hao-Li Zhang;Jiannian Yao
Journal of Materials Chemistry C 2017 vol. 5(Issue 5) pp:1224-1230
Publication Date(Web):2017/02/02
DOI:10.1039/C6TC04129A
Near-infrared (NIR) emission and two-photon excited fluorescence (TPEF) are both desirable features for bioimaging because they offer several advantages, such as deep tissue penetration, high spatial resolution and low background noise. However, incorporation of NIR emission and TPEF into the same labeling dye molecule remains a formidable challenge as it requires three features simultaneously: large two-photon absorption cross-section (δ), high fluorescence quantum yield (Φ) and an appropriate NIR absorption/emission wavelength. Herein, we report a theory-assisted design of novel benzoindolic squaraine (BIS) dye molecules that exhibit a high-performance NIR emission and TPEF properties simultaneously. First, the planarity of the BIS core extended the π-framework, which leads to NIR emission at 682 nm with a quantum yield greater than 40%. Second, we utilized the local electric field effect by the addition of non-conjugated D/A moieties to the BIS core to modulate the two-photon absorption (TPA) cross-section (δ) values. Natural transition orbital calculations suggest that non-conjugated D or A groups do not affect the one-photon photophysical properties of BIS dyes, but can alter the molecular orbitals involved in the Sn ← S0 (n ≥ 2) TPA process. With this new strategy, we successfully obtained a methoxyl-modified molecule (BIS-1), which presents a TPA window between 780 and 950 nm, with the largest δ value above 12 000 GM.
Co-reporter:Xianhu Liu;Weihua Ding;Yishi Wu;Chenghui Zeng;Zhixun Luo
Nanoscale (2009-Present) 2017 vol. 9(Issue 11) pp:3986-3994
Publication Date(Web):2017/03/17
DOI:10.1039/C6NR09818E
We report the synthesis of penicillamine-protected Ag20 nanoclusters (NCs), with properties of high monodispersity, red fluorescence and water solubility. Full characterization of the Ag20 NCs is addressed, along with first-principles optimization calculations, revealing the chemical composition and structure of the as-prepared Ag NCs within a molecular formula [Ag20(DPA)18-H]−. Moreover, natural bond orbital (NBO) analysis demonstrates the charge-transfer interactions between the ligand and Ag atoms, and helps in understanding the origins of fluorescence of Ag20 NCs related to the ligand-to-metal charge transfer (LMCT) mechanism. Further, fluorescence chemosensing of the Ag20 NCs is demonstrated for tracing copper ions with high sensitivity and selectivity in aqueous solution.
Co-reporter:Haihua Zhang;Qing Liao;Yishi Wu;Jianwei Chen;Qinggang Gao
Physical Chemistry Chemical Physics 2017 vol. 19(Issue 43) pp:29092-29098
Publication Date(Web):2017/11/08
DOI:10.1039/C7CP06097A
Zero-dimensional (0D) perovskite Cs4PbBr6 has been speculated to be an efficient solid-state emitter, exhibiting strong luminescense on achieving quantum confinement. Although several groups have reported strong green luminescence from Cs4PbBr6 powders and nanocrystals, doubts that the origin of luminescence comes from Cs4PbBr6 itself or CsPbBr3 impurities have been a point of controversy in recent investigations. Herein, we developed a facile one-step solution self-assembly method to synthesize pure zero-dimensional rhombohedral Cs4PbBr6 micro-disks (MDs) with a high PLQY of 52% ± 5% and photoluminescence full-width at half maximum (FWHM) of 16.8 nm. The obtained rhombohedral MDs were high quality single-crystalline as demonstrated by XRD and SAED patterns. We demonstrated that Cs4PbBr6 MDs and CsPbBr3 MDs were phase-separated from each other and the strong green emission comes from Cs4PbBr6. Power and temperature dependence spectra evidenced that the observed strong green luminescence of pure Cs4PbBr6 MDs originated from direct exciton recombination in the isolated octahedra with a large binding energy of 303.9 meV. Significantly, isolated PbBr64− octahedra separated by a Cs+ ion insert in the crystal lattice is beneficial to maintaining the structural stability, depicting superior thermal and anion exchange stability. Our study provides an efficient approach to obtain high quality single-crystalline Cs4PbBr6 MDs with highly efficient luminescence and stability for further optoelectronic applications.
Co-reporter:Jianwei Chen;Yi Chen;Yishi Wu;Xuedong Wang;Zhenyi Yu;Lu Xiao;Yanping Liu;He Tian;Jiannian Yao
New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 4) pp:1864-1871
Publication Date(Web):2017/02/13
DOI:10.1039/C6NJ02747D
In the field of organic light-emitting diodes (OLEDs), research interests focus on making the optically dark triplet excitons shine in order to increase the electro-optic conversion efficiency of devices. In this work, two kinds of phenazine compounds, i.e. dibenzo[a,c]phenazine (DBP) and tribenzo[a,c,i]phenazine (TBP), were synthesized and used as model compounds to regulate the emission efficiency of the dark triplet excitons by chemical modification. Charge-transfer induced ultrafast intersystem crossing (CT-ISC) with a time constant of ∼1 ps was observed for these two phenazine derivatives upon photoexcitation with a high triplet yield of 77.1% for DBP and 58.7% for TBP. The triplet excited states of DBP can produce ultra-long phosphorescence with lifetime as long as 318 ms at 77 K. The quantum yield for phosphorescence (ΦP) is determined to be 8.45%. In sharp contrast, the triplet-excited 3TBP* undergoes an efficient reverse intersystem crossing (RISC) process, resulting in bright delayed fluorescence emission with negligible phosphorescence. A controllable luminescence behavior from the triplet states between fluorescence and phosphorescence in phenazine derivatives is demonstrated. Theoretical calculations reveal that the structure-dependent triplet evolution is due to the charge-transfer induced energy level alignment within these compounds. Our results may have potential applications in the design of OLEDs and high triplet yield pure organic materials.
Co-reporter:Xuedong Wang;Zhi-Zhou Li;Shi-Feng Li;Hui Li;Jianwei Chen;Yishi Wu
Advanced Optical Materials 2017 Volume 5(Issue 12) pp:
Publication Date(Web):2017/06/01
DOI:10.1002/adom.201700027
Organic solid-state lasers (OSSLs) are broadly tunable coherent sources, potentially compact, convenient, and manufactured at low costs. As compared with conventional organic materials, organic molecules with excited state intramolecular proton-transfer (ESIPT) process are excellent active laser medium candidates due to their inherent four-level system. This study demonstrates the effect of the polymorphism-dependent ESIPT on the OSSLs. It is found the α-phase crystals with a low photoluminescence quantum efficiency of ≈2% emit two components: the tautomer A emissions and the tautomer B emissions, which indicate the noncomplete ESIPT case. For comparison, the β-phase crystals with moderate intramolecular hydrogen-bonding emitting near-infrared photoluminescence have all tautomer B emissions, which are of relatively high photoluminescence quantum efficiency (≈15%) and are red-shifted by an average of ≈250 nm from the corresponding absorptions. The complete ESIPT process of the β-phase crystals contributes to the amplified spontaneous near-infrared emission (λ ≈ 730 nm) with a low threshold of ≈1.86 µJ cm−2. This work has provided the platform for the investigation of the ESIPT lasers, which contributes to the high-performance organic solid-state near-infrared laser devices.
Co-reporter:Xuedong Wang;Zhi-Zhou Li;Ming-Peng Zhuo;Yishi Wu;Shuo Chen;Jiannian Yao
Advanced Functional Materials 2017 Volume 27(Issue 45) pp:
Publication Date(Web):2017/12/01
DOI:10.1002/adfm.201703470
AbstractOrganic semiconductor nanowires have inherent advantages, such as amenability to low-cost, low-temperature processing, and inherent four-level energy systems, which will significantly contribute to the organic solid-state lasers (OSSLs) and miniaturized laser devices. However, the realization of near-infrared (NIR) organic nanowire lasers is always a big challenge due to the difficultly in fabrication of organic nanowires with diameters of ≈100 nm and material issues such as low photoluminescence quantum efficiency in the red-NIR region. What is more, the achievement of wavelength-tunable OSSLs has also encountered enormous challenge. This study first demonstrates the 720 nm NIR lasing with a low lasing threshold of ≈1.4 µJ cm−2 from the organic single-crystalline nanowires, which are self-assembled from small organic molecules of (E)-3-(4-(dimethylamino)-2-methoxyphenyl)-1-(1-hydroxynaphthalen-2-yl)prop-2-en-1-one through a facile solution-phase growth method. Notably, these individual nanowires' Fabry–Pérot cavity can alternatively provide the red-NIR lasing action at 660 or 720 nm from the 0–1 or 0–2 radiative transition channels, and the single (660 or 720 nm)/dual-wavelength (660 and 720 nm) laser action can be achieved by modulating the length of these organic nanowires due to the intrinsic self-absorption. These easily-fabricated organic nanowires are natural laser sources, which offer considerable promise for coherent light devices integrated on the optics microchip.
Co-reporter:You-Dan Zhang; Yishi Wu; Yanqing Xu; Qiang Wang; Ke Liu; Jian-Wei Chen; Jing-Jing Cao; Chunfeng Zhang; Hongbing Fu;Hao-Li Zhang
Journal of the American Chemical Society 2016 Volume 138(Issue 21) pp:6739-6745
Publication Date(Web):May 11, 2016
DOI:10.1021/jacs.6b03829
The energy difference between a singlet exciton and twice of a triplet exciton, ΔESF, provides the thermodynamic driving force for singlet exciton fission (SF). This work reports a systematic investigation on the effect of ΔESF on SF efficiency of five heteroacenes in their solutions. The low-temperature, near-infrared phosphorescence spectra gave the energy levels of the triplet excitons, allowing us to identify the values of ΔESF, which are −0.58, −0.34, −0.31, −0.32, and −0.34 eV for the thiophene, benzene, pyridine, and two tetrafluorobenzene terminated molecules, respectively. Corresponding SF efficiencies of the five heteroacenes in 0.02 M solutions were determined via femtosecond transient absorption spectroscopy to be 117%, 124%, 140%, 132%, and 135%, respectively. This result reveals that higher ΔESF is not, as commonly expected, always beneficial for higher SF efficiency in solution phase. On the contrary, excessive exoergicity results in reduction of SF efficiency in the heteroacenes due to the promotion of other competitive exciton relaxation pathways. Therefore, it is important to optimize thermodynamic driving force when designing organic materials for high SF efficiency.
Co-reporter:Hongtao Lin, Yishi Wu, Zhenyi Yu and Hongbing Fu
New Journal of Chemistry 2016 vol. 40(Issue 2) pp:1610-1617
Publication Date(Web):01 Dec 2015
DOI:10.1039/C5NJ02192H
Photoinitiated interfacial electron transfer from organic semiconductors to inorganic ones is extremely important in organic/inorganic hybrid optoelectronic materials. Herein, we have prepared hybrid ZnO nanorods by grafting TDPP and TTDPP molecules through carboxyl acid groups. The steady-state spectroscopy results revealed that photoluminescence was subjected to severe quenching in the hybrid nanocomposites. Furthermore, time-resolved fluorescence and femtosecond transient absorption data verified the occurrence of the interface charge transfer between TDPP or TTDPP molecules and ZnO nanorods in the hybrid nanocomposites. The high performance UV-vis photodetector based on the TTDPP/ZnO hybrid have been fabricated with a photoresponsivity of 16.9 A W−1 and an on/off ratio as high as 104. The excellent visible-light photoresponse of the hybrid device can be attributed to the broadband absorption after the anchoring of the TTDPP compound on the surface of ZnO nanorods, the efficient cascade charge transfer process and the excellent capability of ZnO nanorods to provide direct and stable pathways for the transport of photogenerated electrons toward the collection electrode. This provides guidelines for the construction of organic/inorganic hybrids for optoelectronic applications.
Co-reporter:Qing Liao;Ke Hu;Haihua Zhang;Xuedong Wang;Jiannian Yao
Advanced Materials 2015 Volume 27( Issue 22) pp:3405-3410
Publication Date(Web):
DOI:10.1002/adma.201500449
Co-reporter:Xuedong Wang; Qing Liao; Hui Li; Shuming Bai; Yishi Wu; Xiaomei Lu; Huaiyuan Hu; Qiang Shi
Journal of the American Chemical Society 2015 Volume 137(Issue 29) pp:9289-9295
Publication Date(Web):July 7, 2015
DOI:10.1021/jacs.5b03051
Near-infrared (NIR) lasers are key components for applications, such as telecommunication, spectroscopy, display, and biomedical tissue imaging. Inorganic III–V semiconductor (GaAs) NIR lasers have achieved great successes but require expensive and sophisticated device fabrication techniques. Organic semiconductors exhibit chemically tunable optoelectronic properties together with self-assembling features that are well suitable for low-temperature solution processing. Major blocks in realizing NIR organic lasing include low stimulated emission of narrow-bandgap molecules due to fast nonradiative decay and exciton–exciton annihilation, which is considered as a main loss channel of population inversion for organic lasers under high carrier densities. Here we designed and synthesized the small organic molecule (E)-3-(4-(di-p-tolylamino)phenyl)-1-(1-hydroxynaphthalen-2-yl)prop-2-en-1-one (DPHP) with amphiphilic nature, which elaborately self-assembles into micrometer-sized hemispheres that simultaneously serves as the NIR emission medium with a photoluminescence quantum efficiency of ∼15.2%, and the high-Q (∼1.4 × 103) whispering gallery mode microcavity. Moreover, the radiative rate of DPHP hemispheres is enhanced up to ∼1.98 × 109 s–1 on account of the exciton-vibrational coupling in the solid state with the J-type molecular-coupling component, and meanwhile the exciton–exciton annihilation process is eliminated. As a result, NIR lasing with a low threshold of ∼610 nJ/cm2 is achieved in the single DPHP hemisphere at room temperature. Our demonstration is a major step toward incorporating the organic coherent light sources into the compact optoelectronic devices at NIR wavelengths.
Co-reporter:Zhenyi Yu; Yishi Wu; Qing Liao; Haihua Zhang; Shuming Bai; Hui Li; Zhenzhen Xu; Chunlin Sun; Xuedong Wang; Jiannian Yao
Journal of the American Chemical Society 2015 Volume 137(Issue 48) pp:15105-15111
Publication Date(Web):November 18, 2015
DOI:10.1021/jacs.5b10353
Organic solid-state lasers (OSSLs) have been a topic of intensive investigations. Perylenediimide (PDI) derivatives are widely used in organic thin-film transistors and solar cells. However, OSSLs based on neat PDIs have not been achieved yet, owing to the formation of H-aggregates and excimer trap-states. Here, we demonstrated the first PDI-based OSSL from whispering-gallery mode (WGM) hexagonal microdisk (hMD) microcavity of N,N′-bis(1-ethylpropyl)-2,5,8,11-tetrakis(p-methyl-phenyl)-perylenediimide (mp-PDI) self-assembled from solution. Single-crystal data reveal that mp-PDI molecules stack into a loosely packed twisted brickstone arrangement, resulting in J-type aggregates that exhibit a solid-state photoluminescence (PL) efficiency φ > 15%. Moreover, we found that exciton-vibration coupling in J-aggregates leads to an exceptional ultrafast radiative decay, which reduces the exciton diffusion length, in turn, suppresses bimolecular exciton annihilation (bmEA) process. These spectral features, plus the optical feedback provided by WGM-hMD microcavity, enable the observation of multimode lasing as evidenced by nonlinear output, spectral narrowing, and temporal coherence of laser emission. With consideration of high carrier-mobility associated with PDIs, hMDs of mp-PDI are attractive candidates on the way to achieve electrically driven OSSL.
Co-reporter:Hui Li, Xuedong Wang, Fangbin Liu and Hongbing Fu
Polymer Chemistry 2015 vol. 6(Issue 17) pp:3283-3289
Publication Date(Web):05 Mar 2015
DOI:10.1039/C5PY00103J
A novel quinacridone-based polymer containing a vinylene linkage, PQTE, was synthesized and exhibited higher performance both in organic thin-film transistors and solar cells than that of the reference polymer PQ2T. On introducing the vinylene linkage, a strong interchain interaction is obtained with a short π–π stacking distance of 3.49 Å in the polymer PQTE, which is responsible for the highest mobility of 0.67 cm2 V−1 s−1 reported to date for quinacridone-based semiconductors. More significantly, the incorporation of a thienylene–vinylene–thienylene unit contributes to good miscibility between PQTE and PC71BM. Because of the effective intercalation of PC71BM in the PQTE lamellar structure, a high power conversion efficiency of 3.9% was achieved without any additives or post-treatments. Our rational molecular design qualifies quinacridone as a promising building block simultaneously in high performance polymer thin-film transistors and solar cells.
Co-reporter:Hui Li, Xiaolin Zheng, Xuedong Wang, Fangbin Liu and Hongbing Fu
Polymer Chemistry 2015 vol. 6(Issue 37) pp:6637-6643
Publication Date(Web):03 Jul 2015
DOI:10.1039/C5PY00790A
Two novel polymers, PDTBO and PD2TBO, containing diketopyrrolopyrrole and alkoxyl-substituted benzothiadiazole were designed and synthesized for polymer photovoltaics. The introduction of thiophene and bithiophene as different π-bridge units results in good planarity of the polymer backbone but a different curvature in polymer chains. The inclusion of bithiophene in the repeat unit leads to a potentially larger curvature and a zigzag conformation for PD2TBO. This increased curvature does not damage the thin-film crystallinity. Instead, high hole mobility is recorded for PD2TBO which is almost two orders of magnitude higher than that of linear PDTBO. Furthermore, high power conversion efficiency (PCE) of 5.3% is obtained for the PD2TBO/PC71BM blend film ascribed to good miscibility while the linear polymer PDTBO exhibits a moderate PCE of 2.1%. Our work demonstrates that the modulation of the chain curvature is an efficient approach to improve the performance of polymer solar cells.
Co-reporter:Jianwei Chen, Yishi Wu, Xuedong Wang, Zhenyi Yu, He Tian, Jiannian Yao and Hongbing Fu
Physical Chemistry Chemical Physics 2015 vol. 17(Issue 41) pp:27658-27664
Publication Date(Web):22 Sep 2015
DOI:10.1039/C5CP04400F
Cryogenic temperature detection plays an irreplaceable role in exploring nature. Developing high sensitivity, accurate, observable and convenient measurements of cryogenic temperature is not only a challenge but also an opportunity for the thermometer field. The small molecule 9-(9,9-dimethyl-9H-fluoren-3yl)-14-phenyl-9,14-dihydrodibenzo[a,c]phenazine (FIPAC) in 2-methyl-tetrahydrofuran (MeTHF) solution is utilized for the detection of cryogenic temperature with a wide range from 138 K to 343 K. This system possesses significantly high sensitivity at low temperature, which reaches as high as 19.4% K−1 at 138 K. The temperature-dependent ratio of the dual emission intensity can be fitted as a single-exponential curve as a function of temperature. This single-exponential curve can be explained by the mechanism that the dual emission feature of FIPAC results from the excited-state configuration transformations upon heating or cooling, which is very different from the previously reported mechanisms. Here, our work gives an overall interpretation for this mechanism. Therefore, application of FIPAC as a cryogenic thermometer is experimentally and theoretically feasible.
Co-reporter:Xingrui Shi, Zhenzhen Xu, Qing Liao, Yishi Wu, Zhanjun Gu, Renhui Zheng, Hongbing Fu
Dyes and Pigments 2015 Volume 115() pp:211-217
Publication Date(Web):April 2015
DOI:10.1016/j.dyepig.2014.12.023
•We synthesized and investigated the photophysical properties of a new donor–π–acceptor molecule BNSN.•BNSN exhibits a red-shifted emission and an unconventional dramatic increase of emission efficiency in polar solvent.•The fluorescence intensity and two-photon absorption cross-section all enhanced when the molecules aggregated.•The nanoparticles of BNSN exhibited aggregation-enhanced two-photon fluorescence in aqueous media.•Cell imaging capability in living cancer cells was examined with low toxicity and high photostability.Two-photon excited fluorescence bio-probes have obtained a great deal of interests in biological imaging and sensing applications. We synthesized a new donor–π–acceptor molecular (BNSN) with strong intramolecular charge-transfer (ICT). Interestingly, different from conventional ICT compounds, BNSN molecules present an unusual ICT phenomenon, leading to a red-shifted emission and an increased fluorescence quantum yield (Φ) with increasing the polarity of solvents. Moreover, the fluorescence intensity and two-photon absorption cross-section all enhanced when the molecules aggregated. The nanoparticles of BNSN exhibit strong two-photon excited fluorescence in aqueous media, exhibiting the property of aggregation-enhanced two-photon fluorescence (AE-TPF). Our results demonstrate that the BNSN molecules with AE-TPF effect provide a new molecular type to construct efficient two-photon excited fluorescence nano-probes for bio-imaging.
Co-reporter:Fangbin Liu, Hui Li, Chunling Gu and Hongbing Fu
RSC Advances 2015 vol. 5(Issue 13) pp:10072-10080
Publication Date(Web):18 Dec 2014
DOI:10.1039/C4RA13351J
Manipulating the alkyl-chain branching position afforded two naphthalene diimide-based polymers (C1 and C3). The optoelectronic properties, including the absorption spectra and electronic energy levels, conformations and photovoltaic properties of the two polymers, were fully studied and compared. The effect of alkyl-chain branching position on their optoelectronic properties and crystallinity was investigated in detail. Moving the branching position away from the backbone resulted in superior crystallinity of C3. All-polymer solar cells (all-PSCs) based on C1 or C3 as the acceptor and polymer PBDTTT-C-T as the donor were fabricated and optimized. The power conversion efficiencies (PCEs) of the optimized all-PSCs based on C1 and C3 reached 1.68% and 1.92%, respectively. The improved photovoltaic performance may be due to the clear nanoscale morphology of C3-based blend film. The blend film exhibits favorable phase separation and well-ordered structure of polymer C3. This substantially increased the electron mobility (up to 1.0 × 10−4 cm2 V−1 s−1), which contributes to balancing the charge transport in C3-based blend film. This is the first report on the realization of favorable phase separation and high electron mobility through improvement of acceptor crystallinity in all-PSCs.
Co-reporter:Xianhu Liu, Yishi Wu, Shuanghao Li, Yan Zhao, Chengqian Yuan, Meiye Jia, Zhixun Luo, Hongbing Fu and Jiannian Yao
RSC Advances 2015 vol. 5(Issue 39) pp:30610-30616
Publication Date(Web):25 Mar 2015
DOI:10.1039/C4RA17239F
We have synthesized monodispersed Au25 nanoclusters (NCs) stabilized with eco-friendly glutathione and report here an insight into their interactions with dye molecules. In the presence of such gold NCs, consistent fluorescence quenching was observed for all the dye molecules that we examined in this study regardless of their maximum emission wavelengths. The steady-state and time-resolved spectroscopic results demonstrate that the weakened luminance is associated with the protective ligand pertaining to a static quenching mechanism. Having expounded this issue, we further employed proper laser irradiation enabling dissociation of Au25(SG)18 so as to attain a transformation of nonplasmonic NCs into plasmonic gold nanoparticles (NPs) via photo-assisted aggregation of the dissociated gold clusters. As a result, emission enhancement for these dyes was observed, which is largely attributed to the local electromagnetic field enhancement of gold NPs. The alternation of fluorescence quenching to emission enhancement reflects an accommodation of quantum size effects upon the ligand-stabilized gold clusters.
Co-reporter:Fangbin Liu, Hui Li, Yishi Wu, Chunling Gu and Hongbing Fu
RSC Advances 2015 vol. 5(Issue 112) pp:92151-92158
Publication Date(Web):20 Oct 2015
DOI:10.1039/C5RA14887A
Donor–acceptor (D–A) copolymers PNDIBTH and PNDIBTOC8 based on two strong electron-deficient units, naphthalene diimide and benzothiadiazole, were synthesized and used as acceptors for the fabrication of all-polymer solar cells (all-PSCs). Introduction of the two octyloxy side chains onto the benzothiadiazole in PNDIBTOC8 could not only increase the solubility and molecular weight of the polymer, but also alter its optical and electronic properties. Compared with PNDIBTH, PNDIBTOC8 possesses a much higher molecular weight and raised LUMO level up to −3.72 eV. Investigation of the photovoltaic performance of two polymers in all-PSCs using polymer PBDTTT-C-T as donor materials indicated that PNDIBTOC8 provides an excellent power conversion efficiency (PCE) of 3.14% with a high open-circuit voltage (Voc) of 0.90 V, much higher than that of the PNDIBTH-based device (PCE of 1.20% with Voc of 0.76 V). Moreover, the dendrite-like phase separation in the PNDIBTOC8-based blend film contributes to the high and more-balanced charge mobilities.
Co-reporter:Ping Wang, Hui Li, Chunling Gu, Huanli Dong, Zhenzhen Xu and Hongbing Fu
RSC Advances 2015 vol. 5(Issue 25) pp:19520-19527
Publication Date(Web):09 Feb 2015
DOI:10.1039/C5RA00391A
Two air-stable polymeric semiconductors were rationally designed and synthesized, namely PNDI-DPP and PNDI-T(DPP)T, containing naphthalenediimide (NDI) units and diketopyrrolopyrrole (DPP). The coplanar thiophene-substituted DPP moieties act as donors rather than acceptors, even though DPP is an electron-deficient core. In a bottom-gate/top-contact device architecture, the effect of changing the number of thiophene linkers on the performance of the two completely different OFETs was investigated. PNDI-T(DPP)T presented unipolar p-type behaviour with an average hole mobility of 0.02 cm2 V−1 s−1, while PNDI-DPP exhibited ambipolar transport with average electron and hole mobilities of 5.7 × 10−3 and 1.6 × 10−3 cm2 V−1 s−1, respectively. Moreover, OFETs based on the two polymers showed good air-stability with negligible changes after being stored under ambient conditions for over 3 months.
Co-reporter:Dr. Qing Liao;Xue Jin;Haihua Zhang;Dr. Zhenzhen Xu; Jiannian Yao; Hongbing Fu
Angewandte Chemie International Edition 2015 Volume 54( Issue 24) pp:7037-7041
Publication Date(Web):
DOI:10.1002/anie.201501060
Abstract
A laser array on the nano- and microscale is a key component for integration in photonic devices, but remains a challenge when using semiconductor nanowire lasers. Here we report a low-threshold lateral-cavity microlaser, formed between two lateral-faces of a single-crystalline organic microbelt (OMB) of 1,4-dimethoxy-2,5-di[4′-(cyano)styryl]benzene (COPV). By cutting a single OMB into six pieces by a top-down two-photon processing technique, we successfully fabricated a compact and uniform 1×6 microlaser array along the length direction of the OMB. The microlasers had excellent reproducibility and addressable high precision, thus making them attractive candidates as miniaturized coherent light sources for future nanophotonics.
Co-reporter:Dr. Qing Liao;Xue Jin;Haihua Zhang;Dr. Zhenzhen Xu; Jiannian Yao; Hongbing Fu
Angewandte Chemie 2015 Volume 127( Issue 24) pp:7143-7147
Publication Date(Web):
DOI:10.1002/ange.201501060
Abstract
A laser array on the nano- and microscale is a key component for integration in photonic devices, but remains a challenge when using semiconductor nanowire lasers. Here we report a low-threshold lateral-cavity microlaser, formed between two lateral-faces of a single-crystalline organic microbelt (OMB) of 1,4-dimethoxy-2,5-di[4′-(cyano)styryl]benzene (COPV). By cutting a single OMB into six pieces by a top-down two-photon processing technique, we successfully fabricated a compact and uniform 1×6 microlaser array along the length direction of the OMB. The microlasers had excellent reproducibility and addressable high precision, thus making them attractive candidates as miniaturized coherent light sources for future nanophotonics.
Co-reporter:Xiaomei Lu
The Journal of Physical Chemistry C 2015 Volume 119(Issue 38) pp:22108-22113
Publication Date(Web):September 8, 2015
DOI:10.1021/acs.jpcc.5b06063
The small organic molecule p-distyrylbenzene (DSB) has been controllably prepared into one-dimensional microwires (1D-MWs) and 2D rhombic microdisks (2D-RMDs) by modulating the growth kinetics in the process of morphology growth. These as-prepared organic microcrystals, 1D-MWs and 2D-RMDs, exhibit a shape-dependent microcavity effect in that the single 1D-MW can act as a Fabry-Pérot (FP) mode lasing resonator while the individual 2D-RMD functions as the whispering-gallery-mode (WGM) microcavity. Moreover, as compared with the 1D FP resonators, there exists a higher quality factor (Q) in the WGM lasing resonator under the identical optical path length. Significantly, the lasing threshold, Eth = 1.02 μJ/cm2, of 2D-RMDs is much lower than Eth = 2.57 μJ/cm2 of 1D-MWs. Our demonstration can give the direction for the development of the organic solid-state microlasers.
Co-reporter:Qinghua Kong ; Qing Liao ; Zhenzhen Xu ; Xuedong Wang ; Jiannian Yao
Journal of the American Chemical Society 2014 Volume 136(Issue 6) pp:2382-2388
Publication Date(Web):January 21, 2014
DOI:10.1021/ja410069k
We report a sequential epitaxial growth to prepare organic branched nanowire heterostructures (BNwHs) consisting of a microribbon trunk of 1,4-dimethoxy-2,5-di[4′-(cyano)styryl]benzene (COPV) with multiple nanowire branches of 2,4,5-triphenylimidazole (TPI) in a one-pot solution synthesis. The synthesis involves a seeded-growth process, where COPV microribbons are grown first as a trunk followed by a seeded-growth of TPI nanowire branches at the pregrown trunk surfaces. Selected area electron diffraction characterizations reveal that multiple hydrogen-bonding interactions between TPI and COPV components play an essential role in the epitaxial growth as a result of the structural matching between COPV and TPI crystals. A multichannel optical router was successfully realized on the basis of the passive waveguides of COPV green photoluminescence (PL) along TPI nanowire branches in a single organic BNwH.
Co-reporter:Xuedong Wang ; Hui Li ; Yishi Wu ; Zhenzhen Xu
Journal of the American Chemical Society 2014 Volume 136(Issue 47) pp:16602-16608
Publication Date(Web):November 4, 2014
DOI:10.1021/ja5088503
Organic single-crystalline micro/nanostructures can effectively generate and carry photons due to their smooth morphologies, high photoluminescence quantum efficiency, and minimized defects density and therefore are potentially ideal building blocks for the optical circuits in the next generation of miniaturized optoelectronics. However, the tailor-made organic molecules can be generally obtained by organic synthesis, ensuring that the organic molecules aggregate in a specific form and generate micro/nanostructures with desirable morphology and therefore act as the efficient laser optical resonator remains a great challenge. Here, the molecular modulation of the morphology on the laser optical resonator properties has been investigated through the preparation of the elongated hexagonal microplates (PHMs) and the rectangular microplates (ORMs), respectively, from two model isomeric organic molecules of 1,4-bis(4-methylstyryl)benzene (p-MSB) and 1,4-bis(2-methylstyryl)benzene (o-MSB). Significantly, fluorescence resonance phenomenon was only observed in the individual ORM other than the PHM. It indicates that the rectangular resonators possess better light-confinement property over the elongated hexagonal resonators. More importantly, optically pumped lasing action was observed in the o-MSB rectangular morphology microplates resonator with a high Q ≈ 1500 above a threshold of ∼540 nJ/cm2. The excellent optical properties of these microstructures are associated with the morphology, which can be precisely modulated by the organic molecular structure. These self-assembled organic microplates with different morphologies can contribute to the distinct functionality of photonics elements in the integrated optical circuits at micro/nanoscale.
Co-reporter:Qing Liao, Zhenzhen Xu, Xiaolan Zhong, Wei Dang, Qiang Shi, Chao Zhang, Yuxiang Weng, Zhiyuan Li and Hongbing Fu
Journal of Materials Chemistry A 2014 vol. 2(Issue 15) pp:2773-2778
Publication Date(Web):29 Jan 2014
DOI:10.1039/C3TC32474E
Development of nanoscale optical components has been an active topic in nanophotonics, with potential for use in high-speed data highways on electronic chips. Organic semiconductors are low-cost advanced materials, exhibiting ease of processing, along with chemically tunable electronic and optical properties. Moreover, the large binding energy and oscillator strength of Frenkel excitons make polaritons in organic semiconductors highly stable at room temperature. Here, we demonstrate a waveguide exciton–polariton (WGEP) sub-microlaser from a built-in Fabry–Pérot (FP) cavity based on self-assembled organic nanowires (ONWs) of 1,4-chloride-2,5-di[4′-(methlthio)styryl-benzene (CDSB). The strong light–matter coupling results in strong optical confinement, enabling ONWs to guide and steer WGEP laser light on the wavelength scale. An optical router was realized using a dendritic structure as a result of efficient polariton waveguiding and photoluminescence (PL) anisotropy of ONWs, opening a new route to future photonic circuits.
Co-reporter:Qing Liao, Haihua Zhang, Weigang Zhu, Ke Hu and Hongbing Fu
Journal of Materials Chemistry A 2014 vol. 2(Issue 45) pp:9695-9700
Publication Date(Web):29 Sep 2014
DOI:10.1039/C4TC01999G
One-dimensional (1D) ribbon-like and two-dimensional (2D) square-like perylene crystals were prepared in a controlled manner via a simple drop-casting solution method by changing the temperature and concentration of the solution. Based on SAED and XRD results, both the ribbon and square perylene crystals belong to the α phase. From further optical and electronic characterizations, we find that perylene crystals show unique dimension-dependent optoelectronic properties. In 2D crystal, photons propagate along the two edge directions without anisotropy, indicating that the optical waveguide property may not be related to molecular packing. Propagation of photons along the direction of the axis in the 1D crystal seems to be a little more efficient than that in the 2D structure. Moreover, hole mobility of the 1D crystal is the same as that along the [001] direction of the 2D square sheet, while hole carriers are transported along the two directions of square sheet with an anisotropy about 2.3. This excellent example shows that the optical waveguide and field-effect mobility of an organic crystal can be tuned by controlling the number of dimensions of the crystal during the synthesis.
Co-reporter:Hui Li, Yishi Wu, Xuedong Wang, Qinghua Kong and Hongbing Fu
Chemical Communications 2014 vol. 50(Issue 75) pp:11000-11003
Publication Date(Web):06 Aug 2014
DOI:10.1039/C4CC04547E
The π-conjugated polymer, PQBOC8, can be easily assembled into a large-area crystalline ultrathin film at the CHCl3/water interface. A phototransistor based on this ultrathin film showed a large photoresponsivity of 970 A W−1, and a photocurrent/dark current ratio of 1.36 × 104 under a very low white light irradiation.
Co-reporter:Huiying Liu, Xinqiang Cao, Yishi Wu, Qing Liao, Ángel J. Jiménez, Frank Würthner and Hongbing Fu
Chemical Communications 2014 vol. 50(Issue 35) pp:4620-4623
Publication Date(Web):07 Mar 2014
DOI:10.1039/C3CC49343A
One-dimensional (1D) rods and 2D hexagonal plates of octachloroperylene diimide (Cl8-PTCDI) have been selectively prepared by controlling the growth kinetic processes. Both ensemble and single-particle spectroscopy clarify that 1D rods and 2D plates have shape dependent optical waveguiding properties.
Co-reporter:Zhenzhen Xu;Qing Liao;Xuedong Wang
Advanced Optical Materials 2014 Volume 2( Issue 12) pp:1160-1166
Publication Date(Web):
DOI:10.1002/adom.201400299
Co-reporter:Xuedong Wang, Qing Liao, Zhenzhen Xu, Yishi Wu, Lang Wei, Xiaomei Lu, and Hongbing Fu
ACS Photonics 2014 Volume 1(Issue 5) pp:413
Publication Date(Web):April 22, 2014
DOI:10.1021/ph400160v
Self-assembled nano/microcrystals of organic semiconductors with regular faces can serve as optical microresonators, which hold a promise for studying the light confinement and the light-matter interaction. Here, single crystalline microribbons of 1,4-bis(2-(4-(N,N-di(p-tolyl)amino)phenyl)-vinylbenzene (DPAVB) are synthesized with well-controlled sizes by a facile solution-exchange method. We find that individual microribbon can work as Fabry-Pérot (FP) resonator along its width (w), in which strong coupling of optical modes with excitons results in the formation of exciton polaritons (EPs). The dispersion relation of E ∼ kz of EPs is constructed by extracting the energies (E) of FP resonances at integer multiples of π/w in the wavevector (kz) space. By simulating the significantly curved dispersion of EPs with a two coupled harmonic oscillator model, a coupling strength between 0.48 and 1.09 eV are obtained. Two coupling regimes are classified: in regime I, the coupling strength is constant at 0.48 eV for microribbons with the cavity length of w ≥ 2.00 μm; in regime II, the coupling strength increases dramatically from 0.48 to about 1 eV with decreasing the resonator length from w = 2.00 to 0.83 μm. More significantly, our results suggest that the exciton-photon coupling strength could be modulated by varying the size of microribbon cavities, providing an effective method for engineering the light–matter interaction in organic single crystalline microstructures.Keywords: light−matter interaction; organic semiconductor; self-assembly; size-tunable
Co-reporter:Yishi Wu, Ke Liu, Huiying Liu, Yi Zhang, Haoli Zhang, Jiannian Yao, and Hongbing Fu
The Journal of Physical Chemistry Letters 2014 Volume 5(Issue 20) pp:3451-3455
Publication Date(Web):September 23, 2014
DOI:10.1021/jz5017729
Singlet fission has attracted considerable interest for its potential application in organic photovoltaics. However, the underlying microscopic mechanism is not well understood and the molecular parameters that govern SF efficiency remain unclear. We herein study the primary exciton photogeneration and evolution in the thin film of a series of pentacene derivatives (TIPS-Pn and ADPD-Pn) using femtosecond transient absorption spectroscopy. With a favorable “long-edge on” packing motif, the singlet-excited slip-stacked TIPS-Pn and ADPD-Pn molecules undergo ultrafast fission to produce triplet excitonic states with time constants of ∼0.3 ps. More importantly, the ADPD-Pn compound features a considerably higher triplet yield than TIPS-Pn (162 ± 10% vs 114 ± 15%). The enhanced electronic coupling as a result of closer interchromophore distance (3.33 Å for ADPD-Pn vs 3.40 Å for TIPS-Pn) is suggested to account for the much higher triplet yield for ADPD-Pn relative to that for TIPS-Pn, proving SF can be readily modulated by adjusting the intermolecular distance.Keywords: Intermolecular coupling; Molecular orientation; Pentacene; Singlet fission; Transient absorption spectroscopy;
Co-reporter:Xuedong Wang;Dr. Qing Liao;Qinghua Kong;Yi Zhang;Zhenzhen Xu;Xiaomei Lu; Hongbing Fu
Angewandte Chemie International Edition 2014 Volume 53( Issue 23) pp:5863-5867
Publication Date(Web):
DOI:10.1002/anie.201310659
Abstract
Whispering-gallery-mode (WGM) resonators of semiconductor microdisks have been applied for achieving low-threshold and narrow-linewidth microlasers, but require sophisticated top-down processing technology. Organic single-crystalline hexagonal microdisks (HMDs) of p-distyrylbenzene (DSB) self-assembled from solution can function as WGM microresonators with a cavity quality factor (Q) of 210. Both multiple- and single-mode lasing had been achieved using DSB HMDs with an edge length of 4.3 and 1.2 μm, respectively. These organic microdisks fabricated by bottom-up self-assembly approach may offer potential applications as low-threshold microlaser sources for photonic circuit integration.
Co-reporter:Chunling Gu, Wenping Hu, Jiannian Yao, and Hongbing Fu
Chemistry of Materials 2013 Volume 25(Issue 10) pp:2178
Publication Date(Web):April 25, 2013
DOI:10.1021/cm401122h
Rational design of air-stable ambipolar polymeric semiconductors was achieved by covalently connecting naphthalenediimide (NDI) units with benzothiadiazole (BZ) through thiophene (T) linkers, namely, PNDI-mT(BZ)mT (m = 1, 2), in which well-coplanar mT(BZ)mT moieties as a whole act as donors rather than acceptors reported in previous studies. Decreasing the number of thiophene linkers from m = 2 to 1 lowers both LUMO and HOMO energy levels. As a result, the carriers in organic thin film transistors (OTFTs) could be switched from unipolar p-channel only to ambipolar transport. In ambient conditions, PNDI-2T(BZ)2T presents an average hole mobility of 0.07 ± 0.02 cm2 V–1 s–1, while PNDI-T(BZ)T exhibits balanced ambipolar charge transport in a bottom-gate/top-contact device architecture, the average electron and hole mobilities was 0.05 ± 0.02 (μe) and 0.1 ± 0.03 (μh) cm2 V–1 s–1, respectively. Moreover, OTFTs based on both polymer show good air-stability with negligible changes after stored in ambient over 3 months.Keywords: air-stable ambipolar polymer semiconductor; balanced ambipolar charge transport; donor−acceptor conjugated copolymer; naphthalene diimide copolymer;
Co-reporter:Zhenzhen Xu, Qing Liao, Xingrui Shi, Hui Li, Haoli Zhang and Hongbing Fu
Journal of Materials Chemistry A 2013 vol. 1(Issue 44) pp:6035-6041
Publication Date(Web):12 Sep 2013
DOI:10.1039/C3TB20841A
Two-photon excited fluorescence (TPEF) bio-probes are important for tissue imaging. Here, we demonstrated a strategy for highly emissive, photostable, low cytotoxicity and full-color tunable TPEF organic nanoparticles (ONPs) comprising of commercially available dyes doped in a TPEF host matrix. Because of efficient Förster resonance energy transfer (FRET), near-IR laser pumping light can be strongly absorbed by host matrix molecules via a two-photon absorption (TPA) process and transferred to dopant dyes, which then emit visible photons in different colors from blue, green, and yellow to red with high quantum yields. Our strategy significantly enhanced the photo-stability and TPEF of dopant dyes in ONPs, avoiding the need to resort to specially engineered expensive dyes.
Co-reporter:Hui Li, Chunling Gu, Lang Jiang, Lang Wei, Wenping Hu and Hongbing Fu
Journal of Materials Chemistry A 2013 vol. 1(Issue 10) pp:2021-2027
Publication Date(Web):16 Jan 2013
DOI:10.1039/C3TC00550J
Two donor–acceptor copolymers, PQB and PQBOC8, containing a donor component quinacridone and an acceptor component benzothiadiazole were synthesized. Introduction of two additional alkoxy chains onto the benzothiadiazole in PQBOC8 not only enhanced solubility and molecular weight but also altered photo-electrochemical properties and polymer chain conformation compared with PQB. As a result, they exhibited different film microstructure and transistor performance. Indeed, PQBOC8 exhibited an ordered lamellar structure with a chain-to-chain distance of 21.5 Å and a π–π stacking distance of 4.0 Å and showed a hole mobility of up to 0.30 cm2 V−1 s−1 in ambient conditions, while PQB revealed a highly disordered film microstructure and a hole mobility of 5.77 × 10−3 cm2 V−1 s−1.
Co-reporter:Huiying Liu, Yishi Wu, Zhaohui Wang, Hongbing Fu
Organic Electronics 2013 Volume 14(Issue 10) pp:2610-2616
Publication Date(Web):October 2013
DOI:10.1016/j.orgel.2013.05.021
•Langmuir–Schaeffer (LS) film transistors were fabricated using diperylene bisimide.•We found that diperylene bisimide molecules stand upright in the multilayer film.•The values of electron mobility increase with increasing the number of LS layers.•Air-stable electron mobility of 0.03 cm2 V−1 s−1 is achieved in an 8-layer transistor.Diperylene Bisimide (DIPP–diPBI) mono- and/or multi-layer film using Langmuir–Schaeffer (LS) techniques has been fabricated and the OFET device performance based on the as-prepared LS film is investigated. The thickness of monolayer film is determined to be 2.3 nm by using atomic force microscopy, which is closely matched with the interplanar spacing estimated from the XRD spectra. The length of molecular long axis is measured to be 21.9 Å from the DFT optimized configuration, indicating that the long axis of molecule in LS film approximately stands upright on hydrophobic substrates. The absorption maximum at 417 nm shows a good linear corrleation with the layer number, proving the obtained films are deposited in a layer-by-layer fassion. The film with precision control of the long-range order and lateral packing density by LS deposition exhibits good electron injection properties and high FET device performance. The charge transport behavior is also investigated as a function of the layer number of LS film. The electron mobility gradually increases with the number of layers and saturates at a plateau with a mean value of 0.03 cm2 V−1 s−1 in the atmosphere upon completion of the first eight layers. It is a direct evidence of physical size of charge transport layer. Furthermore, the fabricated FET device exhibits long-time stability in the air. The integration of LS method with air stability of the n-type compound affords an opportunity to explore solution-phase self-assembly and electronic devices fabrication with controllable molecular layers.Graphical abstract
Co-reporter:Yishi Wu, Yonggang Zhen, Zhaohui Wang, and Hongbing Fu
The Journal of Physical Chemistry A 2013 Volume 117(Issue 8) pp:1712-1720
Publication Date(Web):February 7, 2013
DOI:10.1021/jp310838w
The first example of donor-linked di(perylene bisimide)s is reported. UV–vis absorption spectra of these newly synthesized dyads showed intense absorption across the entire visible region, demonstrating their excellent light-harvesting activities. The severe fluorescence quenching event probed by steady-state fluorescence spectroscopy and the free-energy calculations suggested the possibility of electron transfer (ET) in these arrays upon photoexcitation. Further femtosecond transient absorption spectra clarified that the fluorescence quenching was due to fast intramolecular ET. The rate of the charge separation (CS) was found to be as high as 1012 s–1 in CH2Cl2. It was suggested that the large ET driving forces, strong donor–acceptor electronic coupling, and relatively small reorganization energy of diPBI accounted for the rapid ET process in a synergic manner. The fate of the generated radical ion pair depended on the solvent used. Rapid charge recombination to ground state occurred for the dyads in polar CH2Cl2 and for diPBI-TPA in nonpolar toluene. However, sufficient 3diPBI* population was attained via efficient spin–orbit coupled intersystem crossing from the charge-separated state for diPBI-PdTPP in toluene. These photophysical properties are interpreted as the cooperation between thermodynamic feasibility and kinetic manipulation.
Co-reporter:Lang Wei, Jiannian Yao, and Hongbing Fu
ACS Nano 2013 Volume 7(Issue 9) pp:7573
Publication Date(Web):August 12, 2013
DOI:10.1021/nn402889h
The size, shape, and crystallinity of organic nanostructures play an important role in their physical properties and are mainly determined by the self-assembling kinetics of molecular components often involving the solvent conditions. Here, we reported a kinetically controlled self-assembly of C60 assisted by the solvent carbon bisulfide (CS2) into single-crystal ultrathin microribbons of 2C60·3CS2, upon mixing the poor solvent isopropyl alcohol with a C60/CS2 stock solution. Surface energy calculations reveal that these microribbons represent a kinetically favored high-energy state as compared with the thermodynamically stable shape of prismatic rods. High-resolution transmission electron microscopy observations clarify that association of CS2 at the nucleation stage helps to guide and rigidify the formation of π–π stacking 1D chains of C60 through the surrounding CS2 cage-like structures, which further act as glue, boosting lateral assembly of as-formed 1D chains into untrathin 2D microribbon single crystals. Precise control over the thickness, width, and length of 2C60·3CS2 microribbons was achieved by manipulation of the growth kinetics through adjusting the solvent conditions. Upon heating to 120 °C, sublimation of CS2 components results in fcc C60 microribbons. We found that both microribbons of solvated monoclinic 2C60·3CS2 and pure fcc C60 exhibit highly sensitive photoconductivity properties with a spectral response range covering UV to visible. The highest on/off ratio of two-terminal photodetectors based on single ribbons reaches around 250, while the responsitivity is about 75.3 A W–1 in the UV region and 90.4 A W–1 in the visible region.Keywords: fullerene; microribbon; nanomaterials; photodetector; self-assembly
Co-reporter:Hui Li, Fangbin Liu, Xuedong Wang, Chunling Gu, Ping Wang, and Hongbing Fu
Macromolecules 2013 Volume 46(Issue 23) pp:9211-9219
Publication Date(Web):November 19, 2013
DOI:10.1021/ma401873s
Three new low bandgap conjugated random copolymers, containing two acceptors diketopyrrolopyrrole (DPP) and benzothiadiazole (BTD) linked by thiophene donors, were designed and synthesized using Pd-catalyzed Stille-coupling methods. The ratio between DPP and BTD was varied from N = 3:7 to 1:1 to 7:3 in the polymer backbones. Thin-film device measurements indicate that these polymers exhibit different trends in field-effect mobilities and photovoltaic properties owing to adjustable nanoscale film morphologies as well as solid-state molecular packing. The hole mobilities reach 0.05, 0.17, and 0.40 cm2 V–1 s–1 for N = 3:7, 1:1, and 7:3 copolymers while bulk heterojuction solar cells fabricated by using N = 3:7, 1:1, and 7:3 copolymers as donor and PC60BM as acceptor show power conversion efficiency of 2.4%, 1.3%, and 0.5%. This work sets up a good example of effectively tuning the crystallinity of thin-film device through easily varying the composition ratios.
Co-reporter:Zhenzhen Xu;Qing Liao;Qiang Shi;Haoli Zhang;Jiannian Yao
Advanced Materials 2012 Volume 24( Issue 35) pp:OP216-OP220
Publication Date(Web):
DOI:10.1002/adma.201201579
Co-reporter:Zhenzhen Xu, Qing Liao, Yishi Wu, Wenlu Ren, Wei Li, Libing Liu, Shu Wang, Zhanjun Gu, Haoli Zhang and Hongbing Fu
Journal of Materials Chemistry A 2012 vol. 22(Issue 34) pp:17737-17743
Publication Date(Web):04 Jul 2012
DOI:10.1039/C2JM33081D
Many two-photon absorption (TPA) organic dyes are water insoluble and suffer from strong fluorescence quenching in aqueous media due to the self-aggregation effect. This seriously limits their applications as two-photon fluorescence (TPF) probes in bio-imaging. By employing a reprecipitation method, we prepared ultrabright water-miscible organic nanoparticles (ONPs) of 1,4-dimethoxy-2,5-di[4′-(cyano)styryl]benzene (COPV). The single-crystal structure reveals that the cooperation between π–π stacking and hydrogen-bonding interactions drives COPV molecules into a brickwork arrangement of J-aggregates, in which the coherent excitation delocalization reaches 2–3 molecules. Due to the superradiance of J-aggregates, COPV ONPs are highly emissive in aqueous media with a quantum yield >0.4; meanwhile, their TPA cross-section is greatly enhanced, probably due to exciton–vibration coupling. As TPF probes, COPV J-aggregate ONPs are 3–4 orders of magnitude brighter than conventional fluorescent dyes and an order of magnitude brighter than quantum dots. Moreover, these ONPs exhibit no obvious cytotoxicity at concentrations as high as 100 μg mL−1. Our results demonstrate that ultrabright J-aggregate ONPs of COPV provide a new strategy to construct efficient TPF nano-probes for bio-imaging.
Co-reporter:Xinqiang Cao, Shuming Bai, Yishi Wu, Qing Liao, Qiang Shi, Hongbing Fu and Jiannian Yao
Chemical Communications 2012 vol. 48(Issue 51) pp:6402-6404
Publication Date(Web):03 May 2012
DOI:10.1039/C2CC32112B
2D self-assembly has been demonstrated in perylenediimides with twisted chromophores, in which the π–π stacked units are interconnected via hydrogen bonding interactions. Spectroscopic measurements and theoretical calculations suggest a weak J-type exciton coupling in the assembly. High photoconductivity of the 2D crystal makes it a promising candidate for further opto-electronic applications.
Co-reporter:Lang Wei, Yilong Lei, Hongbing Fu, and Jiannian Yao
ACS Applied Materials & Interfaces 2012 Volume 4(Issue 3) pp:1594
Publication Date(Web):March 5, 2012
DOI:10.1021/am201769u
We developed an electrocatalytic sensor based on C60 hollow microspheres for highly sensitive and selective detection of dopamine (DA) in the presence of ascorbic acid (AA), and uric acid (UA) in the presence of l-cysteine (RSH). The hollow microspheres of C60 with a diameter controllable in the range of 0.5 to 1.5 μm and a thickness of 200 nm are synthesized by a high-temperature reprecipitation method with the assistance of alcohol bubbles. The superhydrophobicity of C60 hollow microspheres makes them capable of forming a compact thin film at air/water interface, which can be readily transferred on the surface of gold or glassy carbon electrodes. This porous C60 film made from C60 hollow microspheres shows a specific surface area as high as 107 m2 g–1. In order to obtain a conducting film, the C60-modified electrode is pretreated by scanning the potential range from 0.0 to −1.5 V in 1 M KOH followed by potential cycling between 550 to −50 mV in a pH 7.2 phosphate buffer solution. On the basis of XPS and IR measurements, we found that surface oxides, such as −OH and C═O groups, are introduced on the surfaces of the conducting C60 film. This, combined with the porosity that enhances the adsorption activity of C60-modified electrodes, enable the electrocatalytic analysis of target biomolecules with detection limit as low as 0.1 nM for DA in the presence of AA, and 1 μM for UA in the presence of RSH.Keywords: biomolecules; C60-modified electrode; electrocatalytic analysis; fullerene; hollow microsphere;
Co-reporter:Huiying Liu, Hui Jia, Lanfen Wang, Yishi Wu, Chuanlang Zhan, Hongbing Fu and Jiannian Yao
Physical Chemistry Chemical Physics 2012 vol. 14(Issue 41) pp:14262-14269
Publication Date(Web):20 Aug 2012
DOI:10.1039/C2CP41288H
The photophysics of a symmetric triad consisting of two bithiophene (BT) units covalently linked to a central diketopyrrolopyrrole unit (DPP) has been investigated both in dichloromethane and in the thin film. The DPP-BT film exhibits a red-shifted low-energy absorption band compared to its solution, which is indicative of efficient π–π interactions in the solid-state phase. The steady-state and time-resolved fluorescence results revealed that the photoluminescence was subjected to severe emission quenching when DPP-BT changes from its solution phase to its film form. Further femtosecond transient absorption studies clarified that rapid intermolecular electron transfer accounts for the considerable fluorescence quenching event. The structural characterization of DPP-BT nanobelts, based on GIXRD and SAED patterns, suggested that the composite may be self-assembled into a slipped face-to-face configuration in the film, providing compact interlayer D–A interactions. As a result, intermolecular electron transfer is promoted by the favorable donor–acceptor attractions between the adjacent molecules. Moreover, this packing configuration provides a moderate channel for charge transportation. The hole mobility, which was measured based on a single-belt field-effect transistor, was found to be around 0.07 cm2 V−1 s−1. Our observation reveals the role of spatial orientation in photophysical processes and the consequential semiconductor performance, providing guidance for the development and self-assembly of new opto-electronic molecules.
Co-reporter:Hongtao Lin, Yishi Wu, Xinqiang Cao, and Hongbing Fu
The Journal of Physical Chemistry C 2012 Volume 116(Issue 41) pp:21657-21663
Publication Date(Web):September 28, 2012
DOI:10.1021/jp3039847
Interfacial electron transfer (IET) plays a key role in photoactive organic/inorganic hybrid nanomaterials and remains elusive with regard to interfacial energy level alignment. In this study, we prepared hybrid ZnO nanorods by grafting n-type perylene bisimide (PBI) derivatives bearing carboxylic acid groups at nitrogen positions. No evidence in terms of direct electron transfer from PBI to ZnO can be observed in PBI/ZnO hybrids. In sharp contrast, incorporation of electron-rich oligothiophene (nT, n = 1, 2) moieties into PBI core at bay positions resulted in a highly efficient cascade IET in nT-PBI/ZnO (n = 1, 2) hybrid nanorods, which was initiated by photoinduced electron transfer (PET) from nT (n = 1, 2) to PBI and then followed by charge shifting from PBI anion to ZnO across the interface. High performance UV–vis photodetectors based on nT-PBI/ZnO (n = 1, 2) hybrids have been fabricated and show responsivity of 21.2 and 12.4 A/W and an on/off ratio as high as 537 and 403, whereas that based on PBI/ZnO shows little visible-light response. Our results suggest that donor–acceptor type compounds can be used for constructing photoactive hybrid nanomaterials, in which efficient cascade IET modifies interfacial electronic structure and helps extend the spectral response range.
Co-reporter:Longtian Kang ; Hongbing Fu ; Xinqiang Cao ; Qiang Shi ;Jiannian Yao
Journal of the American Chemical Society 2011 Volume 133(Issue 6) pp:1895-1901
Publication Date(Web):January 18, 2011
DOI:10.1021/ja108730u
Morphological control of organic nanocrystals (ONCs) is important in the fields ranging from specialty chemicals to molecular semiconductors. Although the thermodynamic shape can be readily predicted, most growth morphologies of ONCs are actually determined by kinetic factors and remain poorly understood. On the basis of the reduction of zinc tetraphenylporphyrin perchlorate (ZnTPP+ClO4−) with sodium nitrite (Na+NO2−), we synthesized two series of ONCs of aquozinc tetraphenylporphyrin (ZnTPP·H2O), in the presence of either cetyltrimethylammonium bromide (CTAB) or poly(vinyl pyrrolidone) (PVP) as the capping ligands. As the cationic precursors of ZnTPP+ are separated in the solution phase, smoothly controlled release of ZnTPP·H2O building blocks via the reduction reaction facilitates the separation between the nucleation and growth stages during the formation of ONCs and provides a high and tunable supersaturation unavailable by employing conventional crystallization techniques. We found that CTAB mainly serve as the colloidal stabilizer, while selective adhesion of PVP on the {020}s facet alters the crystal habits significantly. In both cases, manipulation of the growth kinetics had been achieved by adjusting the concentration of ZnTPP·H2O growth units, and consequently, the supersaturation for the crystallization, thus yielding ONCs with well-controlled sizes and shapes. Remarkably, thermodynamically stable octahedrons have been obtained at high supersaturation in both CTAB and PVP cases.
Co-reporter:Yuchao Ma, Yishi Wu, Yanxia Zhao, Hongbing Fu and Jiannian Yao
Physical Chemistry Chemical Physics 2011 vol. 13(Issue 6) pp:2036-2043
Publication Date(Web):29 Oct 2010
DOI:10.1039/C0CP01166E
A series of monodisperse oligomers consisting of alternating thiophene (T) and perylene bisimide (P), denoted as (TP)nT (n = 1, 2, 3, 6), were synthesized and photophysically characterized. The steady-state absorption and fluorescence spectra revealed that the low-energy P-derived band remains almost unchanged upon the increment of the number of the repeat unit n. This can be rationalized as a consequence of nearly orthogonal molecular geometry and highly-localized electron density at LUMO level based on DFT calculation. A drastic reduction of the fluorescence quantum yields (ΦF) of (TP)nT was observed with the sequence of (TP)6T > (TP)3T > (TP)2T > (TP)1T, as compared to the parent perylene bisimide. Further femtosecond transient absorption studies clarified that the quenching mechanism is intramolecular electron transfer, in which the generated P radical anion was spectrally recognized. The rate of charge separation was found to be on the order of 1011 s−1, suggesting an efficient electron transfer reaction between the thiophene and perylene units. Interestingly, the charge separation rate constant increased more than three times upon the increment of n, whereas the charge-recombination rate constant remained almost unchanged at (1.58–2.21) × 109 s−1. Analysis of the kinetic and thermodynamic data using the Marcus approach showed that the enhanced electronic coupling is the origin of the acceleration of electron-transfer reaction in the D–A copolymers.
Co-reporter:Dr. Qing Liao; Hongbing Fu;Chen Wang ; Jiannian Yao
Angewandte Chemie International Edition 2011 Volume 50( Issue 21) pp:
Publication Date(Web):
DOI:10.1002/anie.201102497
Co-reporter:Dr. Qing Liao; Hongbing Fu;Chen Wang ; Jiannian Yao
Angewandte Chemie International Edition 2011 Volume 50( Issue 21) pp:4942-4946
Publication Date(Web):
DOI:10.1002/anie.201006681
Co-reporter:Dr. Qing Liao; Hongbing Fu;Chen Wang ; Jiannian Yao
Angewandte Chemie 2011 Volume 123( Issue 21) pp:
Publication Date(Web):
DOI:10.1002/ange.201102497
Co-reporter:Dr. Qing Liao; Hongbing Fu;Chen Wang ; Jiannian Yao
Angewandte Chemie 2011 Volume 123( Issue 21) pp:5044-5048
Publication Date(Web):
DOI:10.1002/ange.201006681
Co-reporter:Dezhong Zhang ; Liang Luo ; Qing Liao ; Hao Wang ; Hongbing Fu ;Jianniao Yao
The Journal of Physical Chemistry C 2011 Volume 115(Issue 5) pp:2360-2365
Publication Date(Web):December 30, 2010
DOI:10.1021/jp1079982
The polypyrrole/ZnS core/shell coaxial nanowires are fabricated through a two-step process with the assistance of anodic aluminum oxide (AAO) templates. First, ZnS nanotube arrays are synthesized within AAO templates by using the metal organic chemical vapor deposition (MOCVD) method. Then, polypyrrole (PPy) is electrochemically deposited into as-prepared ZnS nanotubes, creating PPy/ZnS core/shell coaxial nanowires. The morphology and structure of PPy/ZnS coaxial nanowires are characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. Fourier-transform infrared (FTIR) spectroscopy verifies that the in-plane deformation vibration of the pyrrole (Py) ring shows a blue shift from 1144 cm−1 in PPy nanowires to 1173 cm−1 in the PPy/ZnS coaxial nanowires. In X-ray photoelectron spectroscopy analysis (XPS), the changes of the N 1s peak and S 2p peak reveal an electron transfer from the ZnS shell to the PPy core in PPy/ZnS coaxial nanowires, which lowers the reduction potential of PPy at the interface to −0.2 V as compared with −0.88 V observed for pure PPy nanowires. The current−voltage (I−V) characteristics of the ZnS nanotube show the semiconducting behavior, while ohmic behavior is observed for the PPy nanowire. Remarkably, the I−V characteristics of a single core−shell coaxial nanowire exhibit a rectification behavior, probably due to electron transfer between PPy and ZnS. Therefore, this kind of core/shell coaxial nanowires, which combine properties of core and shell materials of different components, might be applicable for nanosccale optoelectronics.
Co-reporter:Xinqiang Cao, Yishi Wu, Hongbing Fu, and Jiannian Yao
The Journal of Physical Chemistry Letters 2011 Volume 2(Issue 17) pp:2163-2167
Publication Date(Web):August 10, 2011
DOI:10.1021/jz2009488
Upon the oxidation of perylenediimide dianion precursors, controlled release of neutral units paves the way for the solution-phase self-assembly of nanobelts via synergistic π–π stacking and hydrogen-bonding interactions. The obtained belt size has been regulated through adjusting the precursor supersaturation. This controlled synthesis also offers us an opportunity to explore size-tunable exciton dynamics features in the nanobelt, in which the competitive evolution to H-like exciton or excimer is found to be in strong relevance to the molecular packing and crystal size.Keywords: exciton dynamics; perylenediimide; self-assembly; wet chemical reaction method;
Co-reporter:Lang Wei ; Yishi Wu ; Lanfen Wang ; Hongbing Fu ;Jiannian Yao
The Journal of Physical Chemistry C 2011 Volume 115(Issue 44) pp:21629-21634
Publication Date(Web):October 4, 2011
DOI:10.1021/jp206155q
A supramolecular method had been developed for the fabrication of C60/tetracene hybrid flowerlike microstructures built of nanoplates. Sequential control of the nucleation and growth of tetracene and C60 components generated first disklike nanocrystals of tetracene about 5 nm in diameter, which then act as seeds for further growth of C60 molecules at its periphery driven by directional CT interactions. As a consequence, embedment of 5 nm tetracene disks in a polycrystalline C60 matrix gives rise to the composite structures of nanoplates, which can interconnect with each other and form complex 3D microspheres. The complete quenching of tetracene fluorescence suggested a highly efficient electron transfer process from tetracene to C60 in flowerlike microstructures. Upon heating to 330 °C, sublimation of tetracene components results in fcc C60 microstructures with the same shape and size as hybrid C60/tetracene microspheres. Moreover, thin films made of either C60/tetracene or fcc C60 flowerlike microstructures featured water-repellent superhydrophobicity with a water contact angle of 150.2 and 156.3°, respectively.
Co-reporter:Yilong Lei ; Qing Liao ; Hongbing Fu ;Jiannian Yao
Journal of the American Chemical Society 2010 Volume 132(Issue 6) pp:1742-1743
Publication Date(Web):January 26, 2010
DOI:10.1021/ja9084435
1D triblock hetrostructures with striping patterns have been synthesized by doping 1,3-diphenyl-2- pyroline (DP) microrods with 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM) molecules selectively at both ends. The middle stripe of triblock microds emit the blue light, while both ends emit orange light due to the efficient FET from excited DP to DCM molecules (right inset). Although triblock microrods show microarea heterogeneity in the striping pattern, they generate macroscopic high-quality white-light emission (WLE) in both the colloidal suspension (left inset) and the solid state with a photoluminescence efficiency as high as 36 ± 5%.
Co-reporter:Yishi Wu, Yonggang Zhen, Yuchao Ma, Renhui Zheng, Zhaohui Wang and Hongbing Fu
The Journal of Physical Chemistry Letters 2010 Volume 1(Issue 17) pp:2499-2502
Publication Date(Web):August 6, 2010
DOI:10.1021/jz1008328
Photosensitized reactions of molecular oxygen have found far-reaching applications in various fields, and the development of new photosensitizer compounds is of crucial importance. We here describe a new class of triply linked bay-fused diperylene bisimides (DiPBIs) which exhibited several unique features, rendering them a new structural platform for the development of highly efficient and photostable photosensitizers. (i) The extended π-conjugation shifts its absorption into the body’s therapeutic window. (ii) The nonplanarity of the distorted cores enhances the spin−orbit coupled intersystem crossing. (iii) The long-lasting high-energy T1 state facilitates singlet oxygen generation via energy-transfer reaction between T1 and ground-state oxygen.Keywords (keywords): intersystem crossing; perylene bisimide; photophysics; photosensitizer; time-resolved spectroscopy;
Co-reporter:Fei Gao;Qing Liao Dr.;Zhen-Zhen Xu;Yong-Hao Yue;Qiang Wang Dr.;Hao-Li Zhang ;Hong-Bing Fu
Angewandte Chemie International Edition 2010 Volume 49( Issue 4) pp:732-735
Publication Date(Web):
DOI:10.1002/anie.200905428
Co-reporter:Qing Liao;Jiannian Yao
Advanced Materials 2009 Volume 21( Issue 41) pp:4153-4157
Publication Date(Web):
DOI:10.1002/adma.200900997
Co-reporter:Hao Wang, Qing Liao, Hongbing Fu, Yi Zeng, Ziwen Jiang, Jinshi Ma and Jiannian Yao
Journal of Materials Chemistry A 2009 vol. 19(Issue 1) pp:89-96
Publication Date(Web):10 Nov 2008
DOI:10.1039/B814007C
We prepared crystalline Ir(ppy)3 microrods through a facile self-assembly growth method by employing the so-called reprecipitation technique, and Ir(ppy)3 nanowires by a solvent-evaporation route. Both have lengths up to several tens of micrometer, but possess significantly different diameters: 1 µm for microrods and 100 nm for nanowires. The electron diffraction (ED) and X-ray diffraction (XRD) results clarify that both microrods and nanowires preferentially grow along the crystal [001] direction. However, the former have a regular hexagonal geometry and single crystalline in nature, while the latter are polycrystalline with a round cross section. Remarkably, microrods and nanowires of Ir(ppy)3 present distinct optical properties. The phosphorescence decay of Ir(ppy)3 microrods and nanowires is much faster than that in degassed solution and polymethylmethacrylate (PMMA) film. The phosphorescence green color of microrods is similar to that of Ir(ppy)3 molecules doped in PMMA films, while nanowires actually emit yellow light probably from the low-energy trap as a result of its polycrystalline nature. Furthermore, the transverse nanoscale and longitudinal microscale dimensions and well-defined faceting nature of microrods enable the observation of evident optical waveguiding. No optically pumped lasing is observed because of intense triplet–triplet exciton annihilation. Our results afford a novel strategy of phosphorescence emission color tuning by controlling the nano- to microstructure dimensions. The microrod phosphorescence waveguides may be used as building blocks for future miniaturized photonic devices.
Co-reporter:Ruili Zhang, Yishi Wu, Zhongliang Wang, Wei Xue, Hongbing Fu and Jiannian Yao
The Journal of Physical Chemistry C 2009 Volume 113(Issue 6) pp:2594-2602
Publication Date(Web):2017-2-22
DOI:10.1021/jp809135j
Aiming at exploring the relationship between the spacer and fluorescence switch properties, we synthesized a series of new photoactive triads, in which one perylenetetracarboxylic diimide unit acting as the electron acceptor was attached to two ferrocene moieties through different spacers. This kind of donor−spacer−acceptor structure allows for tuning one of the key factors that governs photoinduced electron transfer, the distance between the electron donor and acceptor units. The excited-state electron-transfer processes were monitored by both steady-state and time-resolved emission as well as transient absorption techniques. It was found that fluorescence intensity of the solution of all triads 1−3 can be reversibly modulated by the electrochemical oxidation and reduction sequentially. More importantly, as the length of the spacer between the donor and acceptor increases, the background fluorescence increased proportionally, but the contrast ratio of the fluorescence decreases. Together these two factors determine the assay sensitivity, and therefore this work is helpful to provide a basis for the rational design of fluorescence switch by optimizing these factors above.
Co-reporter:Jie Huang, Yishi Wu, Hongbing Fu, Xiaowei Zhan, Jiannian Yao, Stephen Barlow and Seth R. Marder
The Journal of Physical Chemistry A 2009 Volume 113(Issue 17) pp:5039-5046
Publication Date(Web):March 30, 2009
DOI:10.1021/jp8107655
The solution photophysical properties of two conjugated dithienothiophene (DTT)-perylene bisimide (PBI) systems—a polymer, poly{[N,N′-bis(2-decyl-tetradecyl)-3,4,9,10-perylene diimide-1,7-diyl]-alt-(dithieno[3,2-b:2′,3′-d]thiophene-2,6-diyl)}, and a small molecule, 1,7-bis(dithieno[3,2-b:2′,3′-d]thiophene-2-yl)-N,N′-bis(2-decyl-tetradecyl)-3,4,9,10-perylene diimide—in solution have been investigated. Strong quenching of the fluorescence of the PBI moiety was observed in both DTT-PBI systems, suggesting the possibility of an efficient intramolecular electron-transfer process. The kinetics of photoinduced electron transfer in the DTT-PBI polymer and monomer in solutions were explored by femtosecond time-resolved transient absorption spectra. It was found that both the rates of charge separation and charge recombination in the DTT-PBI polymer were approximately double those in the small molecule. This indicates that electronic coupling plays an important role in the electron-transfer process in a polymer system.
Co-reporter:Yilong Lei, Qing Liao, Hongbing Fu and Jiannian Yao
The Journal of Physical Chemistry C 2009 Volume 113(Issue 23) pp:10038-10043
Publication Date(Web):May 13, 2009
DOI:10.1021/jp901357t
Two-dimensional single-crystalline nanostructures of perylene with uniform square and rhombus shapes have been prepared successfully via a simple reprecipitation method with the assistance of surfactant CTAB templates. The X-ray diffraction (XRD) measurements reveal that the square and rhombus nanosheets can be indexed to α- and β-phase perylene crystals, respectively. On the basis of the analysis of time-dependent growth processes, we found that selective adhesion of CTAB molecules on the crystal (001) plane facilitates to the formation of sheetlike structures, whereas polymorph transition from α- to β-phase achieved by altering the surfactant CTAB concentration results in the evolution of the nanosheet from square to rhombus morphologies. Single-nanoparticle spectrscopy depicts that square and rhombus nanosheets show distinct shape-dependent optical properties that are directly related to their crystal structures. Furthermore, the optical waveguiding behaviors have been revealed through the scanning near-field optical microscopy (SNOM) technique. This expands the optical waveguides from 1D to 2D nanostructures and has a potential application in novel optoelectronic devices.
Co-reporter:Zongwei Cao, Hongbing Fu, Longtian Kang, Liwei Huang, Tianyou Zhai, Ying Ma and Jiannian Yao
Journal of Materials Chemistry A 2008 vol. 18(Issue 23) pp:2673-2678
Publication Date(Web):31 Mar 2008
DOI:10.1039/B800691A
We report a rapid (within 15 minutes), simple, green, inexpensive, versatile, and reproducible method for the synthesis of Ag triangular and hexagonal nanoplates in aqueous phase under ambient atmosphere. The method involves reducing silver oxide (Ag2O) with hydrazine (N2H4) in the presence of trisodium citrate (TSC) and ethylenediaminetetraacetic acid disodium salt dihydrate (EDTA) in aqueous phase. In our system, TSC molecules serve as colloidal stabilizers to prevent as-prepared colloids from aggregating, while EDTA molecules serve as a ligand to monomers. The complexation of EDTA to Ag+ not only significantly slows the reduction kinetics of Ag+ by N2H4, but also kinetically controls the formation and growth of nanoplates. By varying the amount of EDTA, the shape (triangular and hexagonal) and edge length of nanoplates have been readily controlled, providing a surface plasmon resonance (SPR) response tunable from visible to near infrared. Most importantly, the SPR response is almost a linear function of the quantity of EDTA. Silver nanocrystals with a required SPR response can be provided, even without considering the actual nature of the Ag colloids. Recent results suggest that this chelation-mediated kinetic control over the sizes and morphologies of nanostructures can also be applied for other metal nanostructures.
Co-reporter:Zongwei Cao, Debao Xiao, Longtian Kang, Zhongliang Wang, Shuxiao Zhang, Ying Ma, Hongbing Fu and Jiannian Yao
Chemical Communications 2008 (Issue 23) pp:2692-2694
Publication Date(Web):14 May 2008
DOI:10.1039/B803959C
Superhydrophobic pure silver film composed of flower-like microstructures built by interconnected silver nanoplates on a copper plate without any modification was prepared by a facile galvanic exchange reaction between the aqueous [Ag(NH3)2]OH and the copper plate, giving rise to a contact angle as high as 157°.
Co-reporter:Yaobing Wang, Zhikun Wu, Zongwei Cao, Longtian Kang, Hongbing Fu, Jin Shi Ma, Jiannian Yao, Boon H. Loo
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2008 Volume 329(1–2) pp:44-50
Publication Date(Web):15 October 2008
DOI:10.1016/j.colsurfa.2008.06.041
Morphological evolution from organic molecules to metallosupramolecules to nanoscale structures is reported. Specifically, bis(iminopyrrole)benzene molecules are coordinated with the ZnII ions to give the characteristic metallosupramolecular architectures of double helicates, triangles and squares. These metallosupramolecules then, as building blocks, aggregate into particular shaped nanostructures such as nanospheres, nanobelts and nanorods. These nanostructures finally coalesce into macroparticles without a variation in shape. The optical properties of the fabricated nanostructures are comparable to those of solution and bulk materials.
Co-reporter:Yaobing Wang, Chuanlang Zhan, Hongbing Fu, Xiao Li, Xiaohai Sheng, Yongsheng Zhao, Debao Xiao, Ying Ma, Jin Shi Ma and Jiannian Yao
Langmuir 2008 Volume 24(Issue 15) pp:7635-7638
Publication Date(Web):June 27, 2008
DOI:10.1021/la801499y
During cooling of the (R)-N-Fmoc-Octylglycine (Fmoc-OG)/cyclohexane solution, gelation is observed exclusively when ultrasound is used as an external stimulus, while deposit is obtained without sonication. The xerogel consists of entangled fibrous network made by interconnected nanofibers, while the deposit comprises large numbers of unbranched nanowires. It is found that the Fmoc-OG molecules form bilayer structures in both the deposit and the gel. However, the ratio (R) between the Fmoc-OG molecules in a stable intramolecular H-bonding conformation and those in a metastable intermolecular H-bonding conformation can be tuned by the ultrasound, R (deposit) > R (gel). The increased population of the intermolecular H-bonding Fmoc-OG molecules induced by the ultrasonication facilitates to the interconnection of nanofibers for the formation of the fibrous network, and therefore gelation. The alteration in the morphologies and properties of the obtained nanomaterials induced by the ultrasound wave demonstrates a potential method for smart controlling of the functions of nanomaterials from the molecular level.
Co-reporter:Longtian Kang, Yu Chen, Debao Xiao, Aidong Peng, Fugang Shen, Xun Kuang, Hongbing Fu and Jiannian Yao
Chemical Communications 2007 (Issue 26) pp:2695-2697
Publication Date(Web):11 Apr 2007
DOI:10.1039/B703283H
We successfully prepared organic core/diffuse-shell nanorods, which presents fluorescence resonance energy transfer from the core to shell components.
Co-reporter:Yaobing Wang, Hongbing Fu, Aidong Peng, Yongsheng Zhao, Jinshi Ma, Ying Ma and Jiannian Yao
Chemical Communications 2007 (Issue 16) pp:1623-1625
Publication Date(Web):23 Mar 2007
DOI:10.1039/B701327B
The effects of molecular structures on nanostructural morphologies have been studied through the preparation of nanospheres, square nanowires, and nanocubes from three isomeric molecules of bis(iminopyrrole)benzene.
Co-reporter:Huiying Liu, Hui Jia, Lanfen Wang, Yishi Wu, Chuanlang Zhan, Hongbing Fu and Jiannian Yao
Physical Chemistry Chemical Physics 2012 - vol. 14(Issue 41) pp:NaN14269-14269
Publication Date(Web):2012/08/20
DOI:10.1039/C2CP41288H
The photophysics of a symmetric triad consisting of two bithiophene (BT) units covalently linked to a central diketopyrrolopyrrole unit (DPP) has been investigated both in dichloromethane and in the thin film. The DPP-BT film exhibits a red-shifted low-energy absorption band compared to its solution, which is indicative of efficient π–π interactions in the solid-state phase. The steady-state and time-resolved fluorescence results revealed that the photoluminescence was subjected to severe emission quenching when DPP-BT changes from its solution phase to its film form. Further femtosecond transient absorption studies clarified that rapid intermolecular electron transfer accounts for the considerable fluorescence quenching event. The structural characterization of DPP-BT nanobelts, based on GIXRD and SAED patterns, suggested that the composite may be self-assembled into a slipped face-to-face configuration in the film, providing compact interlayer D–A interactions. As a result, intermolecular electron transfer is promoted by the favorable donor–acceptor attractions between the adjacent molecules. Moreover, this packing configuration provides a moderate channel for charge transportation. The hole mobility, which was measured based on a single-belt field-effect transistor, was found to be around 0.07 cm2 V−1 s−1. Our observation reveals the role of spatial orientation in photophysical processes and the consequential semiconductor performance, providing guidance for the development and self-assembly of new opto-electronic molecules.
Co-reporter:Zhenzhen Xu, Qing Liao, Xingrui Shi, Hui Li, Haoli Zhang and Hongbing Fu
Journal of Materials Chemistry A 2013 - vol. 1(Issue 44) pp:NaN6041-6041
Publication Date(Web):2013/09/12
DOI:10.1039/C3TB20841A
Two-photon excited fluorescence (TPEF) bio-probes are important for tissue imaging. Here, we demonstrated a strategy for highly emissive, photostable, low cytotoxicity and full-color tunable TPEF organic nanoparticles (ONPs) comprising of commercially available dyes doped in a TPEF host matrix. Because of efficient Förster resonance energy transfer (FRET), near-IR laser pumping light can be strongly absorbed by host matrix molecules via a two-photon absorption (TPA) process and transferred to dopant dyes, which then emit visible photons in different colors from blue, green, and yellow to red with high quantum yields. Our strategy significantly enhanced the photo-stability and TPEF of dopant dyes in ONPs, avoiding the need to resort to specially engineered expensive dyes.
Co-reporter:Chun-Lin Sun, Shao-Kai Lv, Yan-Ping Liu, Qing Liao, Hao-Li Zhang, Hongbing Fu and Jiannian Yao
Journal of Materials Chemistry A 2017 - vol. 5(Issue 5) pp:NaN1230-1230
Publication Date(Web):2016/12/29
DOI:10.1039/C6TC04129A
Near-infrared (NIR) emission and two-photon excited fluorescence (TPEF) are both desirable features for bioimaging because they offer several advantages, such as deep tissue penetration, high spatial resolution and low background noise. However, incorporation of NIR emission and TPEF into the same labeling dye molecule remains a formidable challenge as it requires three features simultaneously: large two-photon absorption cross-section (δ), high fluorescence quantum yield (Φ) and an appropriate NIR absorption/emission wavelength. Herein, we report a theory-assisted design of novel benzoindolic squaraine (BIS) dye molecules that exhibit a high-performance NIR emission and TPEF properties simultaneously. First, the planarity of the BIS core extended the π-framework, which leads to NIR emission at 682 nm with a quantum yield greater than 40%. Second, we utilized the local electric field effect by the addition of non-conjugated D/A moieties to the BIS core to modulate the two-photon absorption (TPA) cross-section (δ) values. Natural transition orbital calculations suggest that non-conjugated D or A groups do not affect the one-photon photophysical properties of BIS dyes, but can alter the molecular orbitals involved in the Sn ← S0 (n ≥ 2) TPA process. With this new strategy, we successfully obtained a methoxyl-modified molecule (BIS-1), which presents a TPA window between 780 and 950 nm, with the largest δ value above 12000 GM.
Co-reporter:Zilong Wang, Peiyang Gu, Guangfeng Liu, Huiying Yao, Yishi Wu, Yongxin Li, Ganguly Rakesh, Jia Zhu, Hongbing Fu and Qichun Zhang
Chemical Communications 2017 - vol. 53(Issue 55) pp:NaN7775-7775
Publication Date(Web):2017/06/19
DOI:10.1039/C7CC03898D
Here, we present our recent progress on the synthesis, crystal structure, physical properties and DFT calculations of a novel large pyrene-fused N-heteroacene (15RINGS) with 15 aromatic six-membered rings linearly fused in one row. The long conjugated backbone (more than 35 Å) of 15RINGS possesses a dual-bending feature (the bending angle is about 13.2°).
Co-reporter:Huiying Liu, Xinqiang Cao, Yishi Wu, Qing Liao, Ángel J. Jiménez, Frank Würthner and Hongbing Fu
Chemical Communications 2014 - vol. 50(Issue 35) pp:NaN4623-4623
Publication Date(Web):2014/03/07
DOI:10.1039/C3CC49343A
One-dimensional (1D) rods and 2D hexagonal plates of octachloroperylene diimide (Cl8-PTCDI) have been selectively prepared by controlling the growth kinetic processes. Both ensemble and single-particle spectroscopy clarify that 1D rods and 2D plates have shape dependent optical waveguiding properties.
Co-reporter:Hui Li, Yishi Wu, Xuedong Wang, Qinghua Kong and Hongbing Fu
Chemical Communications 2014 - vol. 50(Issue 75) pp:NaN11003-11003
Publication Date(Web):2014/08/06
DOI:10.1039/C4CC04547E
The π-conjugated polymer, PQBOC8, can be easily assembled into a large-area crystalline ultrathin film at the CHCl3/water interface. A phototransistor based on this ultrathin film showed a large photoresponsivity of 970 A W−1, and a photocurrent/dark current ratio of 1.36 × 104 under a very low white light irradiation.
Co-reporter:Xinqiang Cao, Shuming Bai, Yishi Wu, Qing Liao, Qiang Shi, Hongbing Fu and Jiannian Yao
Chemical Communications 2012 - vol. 48(Issue 51) pp:NaN6404-6404
Publication Date(Web):2012/05/03
DOI:10.1039/C2CC32112B
2D self-assembly has been demonstrated in perylenediimides with twisted chromophores, in which the π–π stacked units are interconnected via hydrogen bonding interactions. Spectroscopic measurements and theoretical calculations suggest a weak J-type exciton coupling in the assembly. High photoconductivity of the 2D crystal makes it a promising candidate for further opto-electronic applications.
Co-reporter:Zongwei Cao, Debao Xiao, Longtian Kang, Zhongliang Wang, Shuxiao Zhang, Ying Ma, Hongbing Fu and Jiannian Yao
Chemical Communications 2008(Issue 23) pp:NaN2694-2694
Publication Date(Web):2008/05/14
DOI:10.1039/B803959C
Superhydrophobic pure silver film composed of flower-like microstructures built by interconnected silver nanoplates on a copper plate without any modification was prepared by a facile galvanic exchange reaction between the aqueous [Ag(NH3)2]OH and the copper plate, giving rise to a contact angle as high as 157°.
Co-reporter:Longtian Kang, Yu Chen, Debao Xiao, Aidong Peng, Fugang Shen, Xun Kuang, Hongbing Fu and Jiannian Yao
Chemical Communications 2007(Issue 26) pp:NaN2697-2697
Publication Date(Web):2007/04/11
DOI:10.1039/B703283H
We successfully prepared organic core/diffuse-shell nanorods, which presents fluorescence resonance energy transfer from the core to shell components.
Co-reporter:Yaobing Wang;Aidong Peng;Yongsheng Zhao;Jinshi Ma;Ying Ma;Jiannian Yao
Chemical Communications 2007(Issue 16) pp:
Publication Date(Web):2007/04/11
DOI:10.1039/B701327B
The effects of molecular structures on nanostructural morphologies have been studied through the preparation of nanospheres, square nanowires, and nanocubes from three isomeric molecules of bis(iminopyrrole)benzene.
Co-reporter:Qing Liao, Zhenzhen Xu, Xiaolan Zhong, Wei Dang, Qiang Shi, Chao Zhang, Yuxiang Weng, Zhiyuan Li and Hongbing Fu
Journal of Materials Chemistry A 2014 - vol. 2(Issue 15) pp:NaN2778-2778
Publication Date(Web):2014/01/29
DOI:10.1039/C3TC32474E
Development of nanoscale optical components has been an active topic in nanophotonics, with potential for use in high-speed data highways on electronic chips. Organic semiconductors are low-cost advanced materials, exhibiting ease of processing, along with chemically tunable electronic and optical properties. Moreover, the large binding energy and oscillator strength of Frenkel excitons make polaritons in organic semiconductors highly stable at room temperature. Here, we demonstrate a waveguide exciton–polariton (WGEP) sub-microlaser from a built-in Fabry–Pérot (FP) cavity based on self-assembled organic nanowires (ONWs) of 1,4-chloride-2,5-di[4′-(methlthio)styryl-benzene (CDSB). The strong light–matter coupling results in strong optical confinement, enabling ONWs to guide and steer WGEP laser light on the wavelength scale. An optical router was realized using a dendritic structure as a result of efficient polariton waveguiding and photoluminescence (PL) anisotropy of ONWs, opening a new route to future photonic circuits.
Co-reporter:Qing Liao, Haihua Zhang, Weigang Zhu, Ke Hu and Hongbing Fu
Journal of Materials Chemistry A 2014 - vol. 2(Issue 45) pp:NaN9700-9700
Publication Date(Web):2014/09/29
DOI:10.1039/C4TC01999G
One-dimensional (1D) ribbon-like and two-dimensional (2D) square-like perylene crystals were prepared in a controlled manner via a simple drop-casting solution method by changing the temperature and concentration of the solution. Based on SAED and XRD results, both the ribbon and square perylene crystals belong to the α phase. From further optical and electronic characterizations, we find that perylene crystals show unique dimension-dependent optoelectronic properties. In 2D crystal, photons propagate along the two edge directions without anisotropy, indicating that the optical waveguide property may not be related to molecular packing. Propagation of photons along the direction of the axis in the 1D crystal seems to be a little more efficient than that in the 2D structure. Moreover, hole mobility of the 1D crystal is the same as that along the [001] direction of the 2D square sheet, while hole carriers are transported along the two directions of square sheet with an anisotropy about 2.3. This excellent example shows that the optical waveguide and field-effect mobility of an organic crystal can be tuned by controlling the number of dimensions of the crystal during the synthesis.
Co-reporter:Hui Li, Chunling Gu, Lang Jiang, Lang Wei, Wenping Hu and Hongbing Fu
Journal of Materials Chemistry A 2013 - vol. 1(Issue 10) pp:NaN2027-2027
Publication Date(Web):2013/01/16
DOI:10.1039/C3TC00550J
Two donor–acceptor copolymers, PQB and PQBOC8, containing a donor component quinacridone and an acceptor component benzothiadiazole were synthesized. Introduction of two additional alkoxy chains onto the benzothiadiazole in PQBOC8 not only enhanced solubility and molecular weight but also altered photo-electrochemical properties and polymer chain conformation compared with PQB. As a result, they exhibited different film microstructure and transistor performance. Indeed, PQBOC8 exhibited an ordered lamellar structure with a chain-to-chain distance of 21.5 Å and a π–π stacking distance of 4.0 Å and showed a hole mobility of up to 0.30 cm2 V−1 s−1 in ambient conditions, while PQB revealed a highly disordered film microstructure and a hole mobility of 5.77 × 10−3 cm2 V−1 s−1.
Co-reporter:Zhenzhen Xu, Qing Liao, Yishi Wu, Wenlu Ren, Wei Li, Libing Liu, Shu Wang, Zhanjun Gu, Haoli Zhang and Hongbing Fu
Journal of Materials Chemistry A 2012 - vol. 22(Issue 34) pp:
Publication Date(Web):
DOI:10.1039/C2JM33081D
Co-reporter:Zongwei Cao, Hongbing Fu, Longtian Kang, Liwei Huang, Tianyou Zhai, Ying Ma and Jiannian Yao
Journal of Materials Chemistry A 2008 - vol. 18(Issue 23) pp:NaN2678-2678
Publication Date(Web):2008/03/31
DOI:10.1039/B800691A
We report a rapid (within 15 minutes), simple, green, inexpensive, versatile, and reproducible method for the synthesis of Ag triangular and hexagonal nanoplates in aqueous phase under ambient atmosphere. The method involves reducing silver oxide (Ag2O) with hydrazine (N2H4) in the presence of trisodium citrate (TSC) and ethylenediaminetetraacetic acid disodium salt dihydrate (EDTA) in aqueous phase. In our system, TSC molecules serve as colloidal stabilizers to prevent as-prepared colloids from aggregating, while EDTA molecules serve as a ligand to monomers. The complexation of EDTA to Ag+ not only significantly slows the reduction kinetics of Ag+ by N2H4, but also kinetically controls the formation and growth of nanoplates. By varying the amount of EDTA, the shape (triangular and hexagonal) and edge length of nanoplates have been readily controlled, providing a surface plasmon resonance (SPR) response tunable from visible to near infrared. Most importantly, the SPR response is almost a linear function of the quantity of EDTA. Silver nanocrystals with a required SPR response can be provided, even without considering the actual nature of the Ag colloids. Recent results suggest that this chelation-mediated kinetic control over the sizes and morphologies of nanostructures can also be applied for other metal nanostructures.
Co-reporter:Hao Wang, Qing Liao, Hongbing Fu, Yi Zeng, Ziwen Jiang, Jinshi Ma and Jiannian Yao
Journal of Materials Chemistry A 2009 - vol. 19(Issue 1) pp:NaN96-96
Publication Date(Web):2008/11/10
DOI:10.1039/B814007C
We prepared crystalline Ir(ppy)3 microrods through a facile self-assembly growth method by employing the so-called reprecipitation technique, and Ir(ppy)3 nanowires by a solvent-evaporation route. Both have lengths up to several tens of micrometer, but possess significantly different diameters: 1 µm for microrods and 100 nm for nanowires. The electron diffraction (ED) and X-ray diffraction (XRD) results clarify that both microrods and nanowires preferentially grow along the crystal [001] direction. However, the former have a regular hexagonal geometry and single crystalline in nature, while the latter are polycrystalline with a round cross section. Remarkably, microrods and nanowires of Ir(ppy)3 present distinct optical properties. The phosphorescence decay of Ir(ppy)3 microrods and nanowires is much faster than that in degassed solution and polymethylmethacrylate (PMMA) film. The phosphorescence green color of microrods is similar to that of Ir(ppy)3 molecules doped in PMMA films, while nanowires actually emit yellow light probably from the low-energy trap as a result of its polycrystalline nature. Furthermore, the transverse nanoscale and longitudinal microscale dimensions and well-defined faceting nature of microrods enable the observation of evident optical waveguiding. No optically pumped lasing is observed because of intense triplet–triplet exciton annihilation. Our results afford a novel strategy of phosphorescence emission color tuning by controlling the nano- to microstructure dimensions. The microrod phosphorescence waveguides may be used as building blocks for future miniaturized photonic devices.
Co-reporter:Yuchao Ma, Yishi Wu, Yanxia Zhao, Hongbing Fu and Jiannian Yao
Physical Chemistry Chemical Physics 2011 - vol. 13(Issue 6) pp:NaN2043-2043
Publication Date(Web):2010/10/29
DOI:10.1039/C0CP01166E
A series of monodisperse oligomers consisting of alternating thiophene (T) and perylene bisimide (P), denoted as (TP)nT (n = 1, 2, 3, 6), were synthesized and photophysically characterized. The steady-state absorption and fluorescence spectra revealed that the low-energy P-derived band remains almost unchanged upon the increment of the number of the repeat unit n. This can be rationalized as a consequence of nearly orthogonal molecular geometry and highly-localized electron density at LUMO level based on DFT calculation. A drastic reduction of the fluorescence quantum yields (ΦF) of (TP)nT was observed with the sequence of (TP)6T > (TP)3T > (TP)2T > (TP)1T, as compared to the parent perylene bisimide. Further femtosecond transient absorption studies clarified that the quenching mechanism is intramolecular electron transfer, in which the generated P radical anion was spectrally recognized. The rate of charge separation was found to be on the order of 1011 s−1, suggesting an efficient electron transfer reaction between the thiophene and perylene units. Interestingly, the charge separation rate constant increased more than three times upon the increment of n, whereas the charge-recombination rate constant remained almost unchanged at (1.58–2.21) × 109 s−1. Analysis of the kinetic and thermodynamic data using the Marcus approach showed that the enhanced electronic coupling is the origin of the acceleration of electron-transfer reaction in the D–A copolymers.
Co-reporter:Jianwei Chen, Yishi Wu, Xuedong Wang, Zhenyi Yu, He Tian, Jiannian Yao and Hongbing Fu
Physical Chemistry Chemical Physics 2015 - vol. 17(Issue 41) pp:NaN27664-27664
Publication Date(Web):2015/09/22
DOI:10.1039/C5CP04400F
Cryogenic temperature detection plays an irreplaceable role in exploring nature. Developing high sensitivity, accurate, observable and convenient measurements of cryogenic temperature is not only a challenge but also an opportunity for the thermometer field. The small molecule 9-(9,9-dimethyl-9H-fluoren-3yl)-14-phenyl-9,14-dihydrodibenzo[a,c]phenazine (FIPAC) in 2-methyl-tetrahydrofuran (MeTHF) solution is utilized for the detection of cryogenic temperature with a wide range from 138 K to 343 K. This system possesses significantly high sensitivity at low temperature, which reaches as high as 19.4% K−1 at 138 K. The temperature-dependent ratio of the dual emission intensity can be fitted as a single-exponential curve as a function of temperature. This single-exponential curve can be explained by the mechanism that the dual emission feature of FIPAC results from the excited-state configuration transformations upon heating or cooling, which is very different from the previously reported mechanisms. Here, our work gives an overall interpretation for this mechanism. Therefore, application of FIPAC as a cryogenic thermometer is experimentally and theoretically feasible.
![Boron,[2-[1-(3,5-dimethyl-2H-pyrrol-2-ylidene-kN)ethyl]-3,5-dimethyl-1H-pyrrolato-kN]difluoro-, (T-4)-](/data/chemimg/110400/121207-31-6.png)
![Boron,[2-[1-(3,5-dimethyl-2H-pyrrol-2-ylidene-kN)ethyl]-3,5-dimethyl-1H-pyrrolato-kN]difluoro-, (T-4)-](/data/chemimg/110400/121207-31-6_b.png)
![Benzene, 1,1'-[2-(4-bromophenyl)-2-phenylethenylidene]bis[4-methoxy-](/data/chemimg/139000/1378502-33-0.png)
![Benzene, 1,1'-[2-(4-bromophenyl)-2-phenylethenylidene]bis[4-methoxy-](/data/chemimg/139000/1378502-33-0_b.png)
![3,6-diamino-9-[2-(methoxycarbonyl)phenyl]xanthylium chloride](/data/chemimg/622800/62669-70-9.png)
![3,6-diamino-9-[2-(methoxycarbonyl)phenyl]xanthylium chloride](/data/chemimg/622800/62669-70-9_b.png)
![Dibenzo[a,c]phenazine](http://img.cochemist.com/ccimg/300/215-64-5.png)
![Dibenzo[a,c]phenazine](http://img.cochemist.com/ccimg/300/215-64-5_b.png)
![Guanidine, N-(2-butyl-2,3-dihydro-1,3-dioxo-1H-benz[de]isoquinolin-6-yl)-](/data/chemimg/139000/1447694-87-2.png)
![Guanidine, N-(2-butyl-2,3-dihydro-1,3-dioxo-1H-benz[de]isoquinolin-6-yl)-](/data/chemimg/139000/1447694-87-2_b.png)
![Guanidine, N-[2,3-dihydro-2-(2-hydroxyethyl)-1,3-dioxo-1H-benz[de]isoquinolin-6-yl]-](/data/chemimg/139000/1447694-86-1.png)
![Guanidine, N-[2,3-dihydro-2-(2-hydroxyethyl)-1,3-dioxo-1H-benz[de]isoquinolin-6-yl]-](/data/chemimg/139000/1447694-86-1_b.png)
![9H-Fluorene, 9-[bis[4-(hexyloxy)phenyl]methylene]-](/data/chemimg/139000/1431753-17-1.png)
![9H-Fluorene, 9-[bis[4-(hexyloxy)phenyl]methylene]-](/data/chemimg/139000/1431753-17-1_b.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone, 4,9-bis(5'-bromo[2,2'-bithiophen]-5-yl)-2,7-bis(2-octyldodecyl)-](/data/chemimg/139000/1431616-97-5.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone, 4,9-bis(5'-bromo[2,2'-bithiophen]-5-yl)-2,7-bis(2-octyldodecyl)-](/data/chemimg/139000/1431616-97-5_b.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone, 4,9-bis([2,2'-bithiophen]-5-yl)-2,7-bis(2-octyldodecyl)-](/data/chemimg/139000/1431616-96-4.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone, 4,9-bis([2,2'-bithiophen]-5-yl)-2,7-bis(2-octyldodecyl)-](/data/chemimg/139000/1431616-96-4_b.png)
![Ferrocene, 1,1''-(4,5,10,11-tetrahydro-4,10-dioctyl-5,11-dioxoisoquino[6,7,8,1-lmna]pyrido[4,3,2-gh][3,8]phenanthroline-2,8-diyl)bis-](/data/chemimg/139000/1426674-69-2.png)
![Ferrocene, 1,1''-(4,5,10,11-tetrahydro-4,10-dioctyl-5,11-dioxoisoquino[6,7,8,1-lmna]pyrido[4,3,2-gh][3,8]phenanthroline-2,8-diyl)bis-](/data/chemimg/139000/1426674-69-2_b.png)
![Ferrocene, 1,1''-[4,5,10,11-tetrahydro-4,10-bis(2-octyldodecyl)-5,11-dioxoisoquino[6,7,8,1-lmna]pyrido[4,3,2-gh][3,8]phenanthroline-2,8-diyl]bis-](/data/chemimg/139000/1426674-65-8.png)
![Ferrocene, 1,1''-[4,5,10,11-tetrahydro-4,10-bis(2-octyldodecyl)-5,11-dioxoisoquino[6,7,8,1-lmna]pyrido[4,3,2-gh][3,8]phenanthroline-2,8-diyl]bis-](/data/chemimg/139000/1426674-65-8_b.png)
![Ferrocene, 1,1''-[(1,2,3,6,7,8-hexahydro-2,7-dioctyl-1,3,6,8-tetraoxobenzo[lmn][3,8]phenanthroline-4,9-diyl)di-2,1-ethynediyl]bis-](/data/chemimg/139000/1426674-55-6.png)
![Ferrocene, 1,1''-[(1,2,3,6,7,8-hexahydro-2,7-dioctyl-1,3,6,8-tetraoxobenzo[lmn][3,8]phenanthroline-4,9-diyl)di-2,1-ethynediyl]bis-](/data/chemimg/139000/1426674-55-6_b.png)
![Ferrocene, 1,1''-[[1,2,3,6,7,8-hexahydro-2,7-bis(2-octyldodecyl)-1,3,6,8-tetraoxobenzo[lmn][3,8]phenanthroline-4,9-diyl]di-2,1-ethynediyl]bis-](/data/chemimg/139000/1426674-52-3.png)
![Ferrocene, 1,1''-[[1,2,3,6,7,8-hexahydro-2,7-bis(2-octyldodecyl)-1,3,6,8-tetraoxobenzo[lmn][3,8]phenanthroline-4,9-diyl]di-2,1-ethynediyl]bis-](/data/chemimg/139000/1426674-52-3_b.png)
![Isoquino[6,7,8,1-lmna]pyrido[4,3,2-gh][3,8]phenanthroline-5,11-dione, 4,10-dihydro-2,8-dimethyl-4,10-bis(2-octyldodecyl)-](/data/chemimg/139000/1426582-27-5.png)
![Isoquino[6,7,8,1-lmna]pyrido[4,3,2-gh][3,8]phenanthroline-5,11-dione, 4,10-dihydro-2,8-dimethyl-4,10-bis(2-octyldodecyl)-](/data/chemimg/139000/1426582-27-5_b.png)
![Isoquino[6,7,8,1-lmna]pyrido[4,3,2-gh][3,8]phenanthroline-5,11-dione, 4,10-dihydro-4,10-bis(2-octyldodecyl)-2,8-bis[4-(trifluoromethyl)phenyl]-](/data/chemimg/139000/1426582-26-4.png)
![Isoquino[6,7,8,1-lmna]pyrido[4,3,2-gh][3,8]phenanthroline-5,11-dione, 4,10-dihydro-4,10-bis(2-octyldodecyl)-2,8-bis[4-(trifluoromethyl)phenyl]-](/data/chemimg/139000/1426582-26-4_b.png)
![Isoquino[6,7,8,1-lmna]pyrido[4,3,2-gh][3,8]phenanthroline-5,11-dione, 4,10-dihydro-4,10-bis(2-octyldodecyl)-2,8-diphenyl-](/data/chemimg/139000/1426582-25-3.png)
![Isoquino[6,7,8,1-lmna]pyrido[4,3,2-gh][3,8]phenanthroline-5,11-dione, 4,10-dihydro-4,10-bis(2-octyldodecyl)-2,8-diphenyl-](/data/chemimg/139000/1426582-25-3_b.png)
![Isoquino[6,7,8,1-lmna]pyrido[4,3,2-gh][3,8]phenanthroline-5,11-dione, 4,10-dihydro-4,10-bis(2-octyldodecyl)-2,8-di-2-thienyl-](/data/chemimg/139000/1426582-24-2.png)
![Isoquino[6,7,8,1-lmna]pyrido[4,3,2-gh][3,8]phenanthroline-5,11-dione, 4,10-dihydro-4,10-bis(2-octyldodecyl)-2,8-di-2-thienyl-](/data/chemimg/139000/1426582-24-2_b.png)
![Isoquino[6,7,8,1-lmna]pyrido[4,3,2-gh][3,8]phenanthroline-5,11-dione, 2,8-bis[4-(diphenylamino)phenyl]-4,10-dihydro-4,10-bis(2-octyldodecyl)-](/data/chemimg/139000/1426582-23-1.png)
![Isoquino[6,7,8,1-lmna]pyrido[4,3,2-gh][3,8]phenanthroline-5,11-dione, 2,8-bis[4-(diphenylamino)phenyl]-4,10-dihydro-4,10-bis(2-octyldodecyl)-](/data/chemimg/139000/1426582-23-1_b.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone, 2,7-bis(2-octyldodecyl)-4,9-di-1-propyn-1-yl-](/data/chemimg/139000/1426582-17-3.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone, 2,7-bis(2-octyldodecyl)-4,9-di-1-propyn-1-yl-](/data/chemimg/139000/1426582-17-3_b.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone, 2,7-bis(2-octyldodecyl)-4,9-bis[2-[4-(trifluoromethyl)phenyl]ethynyl]-](/data/chemimg/139000/1426582-16-2.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone, 2,7-bis(2-octyldodecyl)-4,9-bis[2-[4-(trifluoromethyl)phenyl]ethynyl]-](/data/chemimg/139000/1426582-16-2_b.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone, 2,7-bis(2-octyldodecyl)-4,9-bis(2-phenylethynyl)-](/data/chemimg/139000/1426582-15-1.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone, 2,7-bis(2-octyldodecyl)-4,9-bis(2-phenylethynyl)-](/data/chemimg/139000/1426582-15-1_b.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone, 2,7-bis(2-octyldodecyl)-4,9-bis[2-(2-thienyl)ethynyl]-](/data/chemimg/139000/1426582-14-0.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone, 2,7-bis(2-octyldodecyl)-4,9-bis[2-(2-thienyl)ethynyl]-](/data/chemimg/139000/1426582-14-0_b.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone, 4,9-bis[2-[4-(diphenylamino)phenyl]ethynyl]-2,7-bis(2-octyldodecyl)-](/data/chemimg/139000/1426582-13-9.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone, 4,9-bis[2-[4-(diphenylamino)phenyl]ethynyl]-2,7-bis(2-octyldodecyl)-](/data/chemimg/139000/1426582-13-9_b.png)
![Pyrido[3,4-g]isoquinoline-1,6-dione, 2,7-dihexyl-2,7-dihydro-3,4,8,9-tetraphenyl-](/data/chemimg/139000/1426400-22-7.png)
![Pyrido[3,4-g]isoquinoline-1,6-dione, 2,7-dihexyl-2,7-dihydro-3,4,8,9-tetraphenyl-](/data/chemimg/139000/1426400-22-7_b.png)
![Pyrido[3,4-g]isoquinolin-1(2H)-one, 2-hexyl-6-(hexyloxy)-3,4,8,9-tetraphenyl-](/data/chemimg/139000/1426400-21-6.png)
![Pyrido[3,4-g]isoquinolin-1(2H)-one, 2-hexyl-6-(hexyloxy)-3,4,8,9-tetraphenyl-](/data/chemimg/139000/1426400-21-6_b.png)
![Pyrido[3,4-g]isoquinoline, 1,6-bis(hexyloxy)-3,4,8,9-tetraphenyl-](/data/chemimg/139000/1426400-20-5.png)
![Pyrido[3,4-g]isoquinoline, 1,6-bis(hexyloxy)-3,4,8,9-tetraphenyl-](/data/chemimg/139000/1426400-20-5_b.png)
![Pyrido[3,4-g]isoquinoline-1,6-dione, 2,7-dihydro-3,4,8,9-tetraphenyl-](/data/chemimg/139000/1426400-19-2.png)
![Pyrido[3,4-g]isoquinoline-1,6-dione, 2,7-dihydro-3,4,8,9-tetraphenyl-](/data/chemimg/139000/1426400-19-2_b.png)
![Quino[2,3-b]acridine-7,14-dione, 2,9-bis(5-bromo-2-thienyl)-5,12-dihydro-5,12-bis(2-octyldodecyl)-](/data/chemimg/139000/1423882-13-6.png)
![Quino[2,3-b]acridine-7,14-dione, 2,9-bis(5-bromo-2-thienyl)-5,12-dihydro-5,12-bis(2-octyldodecyl)-](/data/chemimg/139000/1423882-13-6_b.png)
![9H-Fluorene, 9-[bis[4-(hexadecyloxy)phenyl]methylene]-](/data/chemimg/139000/1417402-41-5.png)
![9H-Fluorene, 9-[bis[4-(hexadecyloxy)phenyl]methylene]-](/data/chemimg/139000/1417402-41-5_b.png)
![9H-Fluorene, 9-[bis[4-(dodecyloxy)phenyl]methylene]-](/data/chemimg/139000/1417402-40-4.png)
![9H-Fluorene, 9-[bis[4-(dodecyloxy)phenyl]methylene]-](/data/chemimg/139000/1417402-40-4_b.png)
![9H-Fluorene, 9-[bis[4-(octyloxy)phenyl]methylene]-](/data/chemimg/139000/1417402-39-1.png)
![9H-Fluorene, 9-[bis[4-(octyloxy)phenyl]methylene]-](/data/chemimg/139000/1417402-39-1_b.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-2,9-diacetic acid, 5,12-bis([2,2'-bithiophen]-5-yl)-1,3,8,10-tetrahydro-1,3,8,10-tetraoxo-](/data/chemimg/139000/1402910-50-2.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-2,9-diacetic acid, 5,12-bis([2,2'-bithiophen]-5-yl)-1,3,8,10-tetrahydro-1,3,8,10-tetraoxo-](/data/chemimg/139000/1402910-50-2_b.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-2,9-diacetic acid, 1,3,8,10-tetrahydro-1,3,8,10-tetraoxo-5,12-di-2-thienyl-](/data/chemimg/139000/1402910-49-9.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-2,9-diacetic acid, 1,3,8,10-tetrahydro-1,3,8,10-tetraoxo-5,12-di-2-thienyl-](/data/chemimg/139000/1402910-49-9_b.png)
![Quino[2,3-b]acridine-7,14-dione, 5,12-dihydro-5,12-bis(2-octyldodecyl)-2,9-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-](/data/chemimg/139000/1400665-71-5.png)
![Quino[2,3-b]acridine-7,14-dione, 5,12-dihydro-5,12-bis(2-octyldodecyl)-2,9-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-](/data/chemimg/139000/1400665-71-5_b.png)
![Quino[2,3-b]acridine-7,14-dione, 2,9-dibromo-5,12-dihydro-5,12-bis(2-octyldodecyl)-](/data/chemimg/139000/1400665-70-4.png)
![Quino[2,3-b]acridine-7,14-dione, 2,9-dibromo-5,12-dihydro-5,12-bis(2-octyldodecyl)-](/data/chemimg/139000/1400665-70-4_b.png)
![Quino[2,3-b]acridine-7,14-dione, 5,12-dihydro-5,12-bis(2-octyldodecyl)-](/data/chemimg/139000/1400665-69-1.png)
![Quino[2,3-b]acridine-7,14-dione, 5,12-dihydro-5,12-bis(2-octyldodecyl)-](/data/chemimg/139000/1400665-69-1_b.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetrone, 5,6,12,13-tetrachloro-, sodium salt (1:2)](http://img.cochemist.com/data/images/1381787-70-7.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetrone, 5,6,12,13-tetrachloro-, sodium salt (1:2)](http://img.cochemist.com/data/images/1381787-70-7_b.png)
![Benzoic acid, 4,4'-(1,1'-didodecyl[3,3'-bi-1H-phenanthro[1,10,9,8-cdefg]carbazole]-10,10'-diyl)bis-](/data/chemimg/139000/1357028-50-2.png)
![Benzoic acid, 4,4'-(1,1'-didodecyl[3,3'-bi-1H-phenanthro[1,10,9,8-cdefg]carbazole]-10,10'-diyl)bis-](/data/chemimg/139000/1357028-50-2_b.png)
![9H-Fluorene, 9-[bis(4-butoxyphenyl)methylene]-](/data/chemimg/139000/1353580-60-5.png)
![9H-Fluorene, 9-[bis(4-butoxyphenyl)methylene]-](/data/chemimg/139000/1353580-60-5_b.png)
![Benzoic acid, 4-(1-dodecyl-1H-phenanthro[1,10,9,8-cdefg]carbazol-3-yl)-, methyl ester](/data/chemimg/139000/1335223-98-7.png)
![Benzoic acid, 4-(1-dodecyl-1H-phenanthro[1,10,9,8-cdefg]carbazol-3-yl)-, methyl ester](/data/chemimg/139000/1335223-98-7_b.png)
![1H-Phenanthro[1,10,9,8-cdefg]carbazole, 3-bromo-1-dodecyl-](/data/chemimg/139000/1335223-97-6.png)
![1H-Phenanthro[1,10,9,8-cdefg]carbazole, 3-bromo-1-dodecyl-](/data/chemimg/139000/1335223-97-6_b.png)
![1H-Phenanthro[1,10,9,8-cdefg]carbazole, 1-dodecyl-](/data/chemimg/139000/1335223-96-5.png)
![1H-Phenanthro[1,10,9,8-cdefg]carbazole, 1-dodecyl-](/data/chemimg/139000/1335223-96-5_b.png)
![Pyrrolo[3,4-c]pyrrole-1,4-dione, 2,5-dihydro-2,5-bis(2-octyldodecyl)-3,6-di-2-thienyl-](/data/chemimg/139000/1267540-02-2.png)
![Pyrrolo[3,4-c]pyrrole-1,4-dione, 2,5-dihydro-2,5-bis(2-octyldodecyl)-3,6-di-2-thienyl-](/data/chemimg/139000/1267540-02-2_b.png)
![Pyrrolo[3,4-c]pyrrole-1,4-dione, 3,6-bis(5-bromo-2-thienyl)-2,5-dihydro-2,5-bis(2-octyldodecyl)-](/data/chemimg/139000/1260685-63-9.png)
![Pyrrolo[3,4-c]pyrrole-1,4-dione, 3,6-bis(5-bromo-2-thienyl)-2,5-dihydro-2,5-bis(2-octyldodecyl)-](/data/chemimg/139000/1260685-63-9_b.png)
![Benzoic acid, 4-[1-(2-hexyldecyl)-1H-phenanthro[1,10,9,8-cdefg]carbazol-3-yl]-, methyl ester](/data/chemimg/139000/1220707-45-8.png)
![Benzoic acid, 4-[1-(2-hexyldecyl)-1H-phenanthro[1,10,9,8-cdefg]carbazol-3-yl]-, methyl ester](/data/chemimg/139000/1220707-45-8_b.png)
![Benzene, 1,4-dimethoxy-2,5-bis[(1E)-2-[4-(methylthio)phenyl]ethenyl]-](/data/chemimg/139000/1217296-18-8.png)
![Benzene, 1,4-dimethoxy-2,5-bis[(1E)-2-[4-(methylthio)phenyl]ethenyl]-](/data/chemimg/139000/1217296-18-8_b.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone, 4,9-bis(5-bromo-2-thienyl)-2,7-bis(2-octyldodecyl)-](/data/chemimg/139000/1178586-27-0.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone, 4,9-bis(5-bromo-2-thienyl)-2,7-bis(2-octyldodecyl)-](/data/chemimg/139000/1178586-27-0_b.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone, 2,7-bis(2-octyldodecyl)-4,9-di-2-thienyl-](/data/chemimg/139000/1178586-26-9.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone, 2,7-bis(2-octyldodecyl)-4,9-di-2-thienyl-](/data/chemimg/139000/1178586-26-9_b.png)
![1H-Phenanthro[1,10,9,8-cdefg]carbazole, 1-(2-hexyldecyl)-](/data/chemimg/139000/1131759-14-2.png)
![1H-Phenanthro[1,10,9,8-cdefg]carbazole, 1-(2-hexyldecyl)-](/data/chemimg/139000/1131759-14-2_b.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetrone, 6,13-bis[4-(1,1-dimethylethyl)phenoxy]-2,9-bis(2-ethylhexyl)-](/data/chemimg/102700/952684-26-3.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetrone, 6,13-bis[4-(1,1-dimethylethyl)phenoxy]-2,9-bis(2-ethylhexyl)-](/data/chemimg/102700/952684-26-3_b.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-2,9-diacetic acid, 5,12-dibromo-1,3,8,10-tetrahydro-1,3,8,10-tetraoxo-](/data/chemimg/102700/931402-32-3.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-2,9-diacetic acid, 5,12-dibromo-1,3,8,10-tetrahydro-1,3,8,10-tetraoxo-](/data/chemimg/102700/931402-32-3_b.png)
![9H-Fluorene, 9-[bis(4-ethoxyphenyl)methylene]-](/data/chemimg/102700/861373-38-8.png)
![9H-Fluorene, 9-[bis(4-ethoxyphenyl)methylene]-](/data/chemimg/102700/861373-38-8_b.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-2,9-diacetic acid, 5,12-dibromo-1,3,8,10-tetrahydro-1,3,8,10-tetraoxo-, bis(1,1-dimethylethyl) ester (9CI)](/data/chemimg/102700/860651-89-4.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-2,9-diacetic acid, 5,12-dibromo-1,3,8,10-tetrahydro-1,3,8,10-tetraoxo-, bis(1,1-dimethylethyl) ester (9CI)](/data/chemimg/102700/860651-89-4_b.png)
![Benzenamine, N,N-diphenyl-4-[2-(tributylstannyl)ethynyl]-](/data/chemimg/102700/607716-34-7.png)
![Benzenamine, N,N-diphenyl-4-[2-(tributylstannyl)ethynyl]-](/data/chemimg/102700/607716-34-7_b.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetrone, 5,6,12,13-tetrakis[4-(1,1-dimethylethyl)phenoxy]-2,9-bis(2-ethylhexyl)- (9CI)](/data/chemimg/102700/318293-22-0.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetrone, 5,6,12,13-tetrakis[4-(1,1-dimethylethyl)phenoxy]-2,9-bis(2-ethylhexyl)- (9CI)](/data/chemimg/102700/318293-22-0_b.png)
![Stannane, tributyl[2-[4-(trifluoromethyl)phenyl]ethynyl]-](/data/chemimg/102700/251905-63-2.png)
![Stannane, tributyl[2-[4-(trifluoromethyl)phenyl]ethynyl]-](/data/chemimg/102700/251905-63-2_b.png)
![Ferrocene, [2-(tributylstannyl)ethynyl]-](/data/chemimg/102700/191600-29-0.png)
![Ferrocene, [2-(tributylstannyl)ethynyl]-](/data/chemimg/102700/191600-29-0_b.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetrone,5,6,12,13-tetrachloro-](/data/chemimg/102600/115662-06-1.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetrone,5,6,12,13-tetrachloro-](/data/chemimg/102600/115662-06-1_b.png)
![1H-Benz[de]isoquinoline-1,3(2H)-dione, 6-bromo-2-butyl-](/data/chemimg/3731700/92874-17-4.png)
![1H-Benz[de]isoquinoline-1,3(2H)-dione, 6-bromo-2-butyl-](/data/chemimg/3731700/92874-17-4_b.png)
![9H-Fluorene, 9-[bis(4-methoxyphenyl)methylene]-](http://img.cochemist.com/ccimg/88600/88534-40-1.png)
![9H-Fluorene, 9-[bis(4-methoxyphenyl)methylene]-](http://img.cochemist.com/ccimg/88600/88534-40-1_b.png)
![[2]Benzopyrano[6,5,4-def][2]benzopyran-1,3,6,8-tetrone, 4,9-dibromo-](/data/chemimg/1015800/83204-68-6.png)
![[2]Benzopyrano[6,5,4-def][2]benzopyran-1,3,6,8-tetrone, 4,9-dibromo-](/data/chemimg/1015800/83204-68-6_b.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetrone, 2,9-bis(2-ethylhexyl)-](/data/chemimg/3730400/82531-03-1.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetrone, 2,9-bis(2-ethylhexyl)-](/data/chemimg/3730400/82531-03-1_b.png)
![1H-Benz[de]isoquinoline-1,3(2H)-dione, 6-bromo-2-(2-hydroxyethyl)-](/data/chemimg/3232400/52559-37-2.png)
![1H-Benz[de]isoquinoline-1,3(2H)-dione, 6-bromo-2-(2-hydroxyethyl)-](/data/chemimg/3232400/52559-37-2_b.png)
![4-[FLUOREN-9-YLIDENE-(4-HYDROXYPHENYL)METHYL]PHENOL](http://img.cochemist.com/ccimg/52300/52258-98-7.png)
![4-[FLUOREN-9-YLIDENE-(4-HYDROXYPHENYL)METHYL]PHENOL](http://img.cochemist.com/ccimg/52300/52258-98-7_b.png)
![2,7-Bis(2-(dimethylamino)ethyl)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone](/data/chemimg/422600/22291-04-9.png)
![2,7-Bis(2-(dimethylamino)ethyl)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone](/data/chemimg/422600/22291-04-9_b.png)
![Molybdate(3-), tetracosa-μ-oxododecaoxo[μ -[phosphato(3-)-κO:κO:κO:κO':κO':κO':κO'':κO'':κO'':κO''':κO''':κO''']]dodeca-](/data/chemimg/3784600/12379-13-4.png)
![Molybdate(3-), tetracosa-μ-oxododecaoxo[μ -[phosphato(3-)-κO:κO:κO:κO':κO':κO':κO'':κO'':κO'':κO''':κO''':κO''']]dodeca-](/data/chemimg/3784600/12379-13-4_b.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone, 4,9-dibromo-2,7-bis(2-octyldodecyl)-](/data/chemimg/139000/1100243-35-3.png)
![Benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetrone, 4,9-dibromo-2,7-bis(2-octyldodecyl)-](/data/chemimg/139000/1100243-35-3_b.png)
![Propanedinitrile, 2-[2-[2-[4-(dimethylamino)phenyl]ethenyl]-6-methyl-4H-pyran-4-ylidene]-](/data/chemimg/2138200/51325-91-8.png)
![Propanedinitrile, 2-[2-[2-[4-(dimethylamino)phenyl]ethenyl]-6-methyl-4H-pyran-4-ylidene]-](/data/chemimg/2138200/51325-91-8_b.png)
