Co-reporter:Suqian Ma, Jibo Zhang, Yingjie Liu, Jingyu Qian, Bin Xu, and Wenjing Tian
The Journal of Physical Chemistry Letters July 6, 2017 Volume 8(Issue 13) pp:3068-3068
Publication Date(Web):June 16, 2017
DOI:10.1021/acs.jpclett.7b01454
The symmetrical and asymmetrical protonation states are realized via the formation of intermolecular hydrogen bonds inside 9,10-bis((E)-2-(pyridin-4-yl)vinyl)anthracene (BP4VA) molecular crystals. With the protonation of H2SO4, BP4VA molecules are protonated symmetrically, while the molecules are asymmetrically protonated by introducing HCl. The different protonation states of BP4VA crystals result in various supramolecular interactions, aggregation states, and even tunable optical properties. It provides a fundamental principle to understand the effect of protonation in organic conjugated molecules and an approach to expanding the scope of organic functional materials.
Co-reporter:Jingyu Qian, Leijing Liu, Bin Xu, Wenjing Tian
Organic Electronics 2017 Volume 42() pp:244-255
Publication Date(Web):March 2017
DOI:10.1016/j.orgel.2016.12.055
•The theoretical carrier mobilities between the same bases of DNA in the range of semiconductors.•The charge transport for both holes and electrons between different bases exhibits directivity.•Compared with the double helix structure, DNA with the bilinear structure possesses better charge transport properties.The charge transport properties of DNA are studied by the first-principle simulation to discuss the possibility of applying DNA to molecular wire. Both the hopping model and band-like model are introduced. By using hopping model, the theoretical hole mobilities calculated by Marcus theory between the same bases in DNA are 5.6 × 10−3, 4.1 × 10−2, 2.0 × 10−2 and 1.2 × 10−4 cm2V−1s−1 for T-T, A-A, C-C and G-G; and the calculated electron mobilities are 5.3 × 10−8, 1.5 × 10−4, 8.1 × 10−7 and 7.5 × 10−10 cm2V−1s−1 for T-T, A-A, C-C and G-G, respectively. And the charge transport for both holes and electrons between different bases exhibits directivity. By using band-like model, we calculated the band width of DNA with double helix structure and bilinear structure to investigate which structure will facilitate to the charge transport. We found that the band width of DNA increased when DNA transforming from the double helix structure to the bilinear structure, which means DNA with the bilinear structure possesses better charge transport properties. This research sheds a light on the molecular design for the molecule serving as the molecular wire.Figure optionsDownload full-size imageDownload high-quality image (270 K)Download as PowerPoint slide
Co-reporter:Yingjie Liu;Suqian Ma;Bin Xu
Faraday Discussions 2017 (Volume 196) pp:219-229
Publication Date(Web):2017/02/20
DOI:10.1039/C6FD00166A
Aggregation-induced emission (AIE) provides a new way of achieving highly efficient luminescent materials. In this contribution, the self-assembly behavior, molecular stacking structure and photophysical properties of two polymorphs of a supramolecular co-crystal (C1 and C2) are investigated. The block-like crystal C1, packed in segregated stacking with strong π–π interactions between the H and G molecules, shows weak green emission with a low efficiency (ΦF) of 2%. In comparison, the needle-like crystal C2, packed in segregated stacking with no obviously strong intermolecular interactions, shows bright yellow emission. More importantly, C1 exhibits mechanochromic behavior.
Co-reporter:Jingyu Qian;Qing Guo;Leijing Liu;Bin Xu
Journal of Materials Chemistry A 2017 vol. 5(Issue 32) pp:16786-16795
Publication Date(Web):2017/08/15
DOI:10.1039/C7TA04008C
The electrical properties, optical properties and stabilities of hybrid lead iodide perovskite homologous semiconductors with 0D, 1D, 2D and 3D structures have been investigated based on their electronic structures calculated by density functional theory (DFT). The results indicated that the power conversion efficiencies (PCEs) estimated according to the absorption spectra of 1D perovskite homologues (1.9–10.9%) and 2D perovskite homologues (4.4–6.9%) are similar. However, the charge transport properties of 1D perovskite homologues (only ∼0% of that of the reference, CH3NH3PbI3) are entirely different from those of 2D perovskite homologues (reaching 43% of that of the reference) when a polycrystalline model has been introduced, although both of them are anisotropic materials. More charge transport paths of 2D perovskite homologues have been found in the polycrystalline state, compared with those of 1D perovskite homologues. Our findings have a great realistic significance to understand the properties of polycrystalline perovskite homologues.
Co-reporter:Jingyu Qian;Qing Guo;Leijing Liu;Bin Xu
Journal of Materials Chemistry A 2017 vol. 5(Issue 32) pp:16786-16795
Publication Date(Web):2017/08/15
DOI:10.1039/C7TA04008C
The electrical properties, optical properties and stabilities of hybrid lead iodide perovskite homologous semiconductors with 0D, 1D, 2D and 3D structures have been investigated based on their electronic structures calculated by density functional theory (DFT). The results indicated that the power conversion efficiencies (PCEs) estimated according to the absorption spectra of 1D perovskite homologues (1.9–10.9%) and 2D perovskite homologues (4.4–6.9%) are similar. However, the charge transport properties of 1D perovskite homologues (only ∼0% of that of the reference, CH3NH3PbI3) are entirely different from those of 2D perovskite homologues (reaching 43% of that of the reference) when a polycrystalline model has been introduced, although both of them are anisotropic materials. More charge transport paths of 2D perovskite homologues have been found in the polycrystalline state, compared with those of 1D perovskite homologues. Our findings have a great realistic significance to understand the properties of polycrystalline perovskite homologues.
Co-reporter:Leijing Liu;Fengli Zhang;Bin Xu
Journal of Materials Chemistry B 2017 vol. 5(Issue 46) pp:9197-9203
Publication Date(Web):2017/11/29
DOI:10.1039/C7TB02734F
Nitric oxide (NO), known as a reactive nitrogen species (RNS), has been considered to be a significant factor in many cell-related biological processes. There is a great desire to develop fluorescent probes that can highly sensitively and selectively detect NO in living cells. Herein, a fluorescent probe, a tetraphenylethene (TPE) derivative TPE-2NH2, with aggregation induced emission (AIE) properties was designed and synthesized. Then silica nanoparticles based on TPE-2NH2 were fabricated for ratiometric detection of NO in vitro with high sensitivity and selectivity. In the presence of NO, the fluorescence of the silica nanoparticles changes from 519 nm (green) to 655 nm (red) because of the chemical reaction between NO and o-phenylenediamine in TPE-2NH2. The silica nanoparticles exhibited very high sensitivity and selectivity towards NO in aqueous buffer, and the response time was as short as 5 minutes. Moreover, the silica nanoparticles can also highly sensitively and selectively respond to NO produced in living cells. When MCF-7 cancer cells were activated by lipopolysaccharides (LPS), which can effectively induce the production of NO, the red emission signal of the silica nanoparticles obviously increased. This demonstrated that the silica nanoparticles showed fine imaging contrast towards NO in MCF-7 cancer cells, which provides a facile tool to detect intracellular NO.
Co-reporter:Jibo Zhang;Suqian Ma;Honghua Fang;Bin Xu;Hongbo Sun;Im Chan
Materials Chemistry Frontiers 2017 vol. 1(Issue 7) pp:1422-1429
Publication Date(Web):2017/06/28
DOI:10.1039/C7QM00032D
9,10-Distyrylanthracene (DSA) and its four derivatives are investigated by both steady state and ultrafast spectroscopy to reveal the intrinsic photophysical process upon excitation. Intramolecular rotation around the vinyl moiety plays an important role in the whole photophysical process in addition to the electronic properties of the peripheral substituents. In dilute solutions, DSA derivatives possess a twisted structure in the ground state that eventually relaxes to a planar structure within picoseconds. The fluorescence process is dominated by the relaxed excited state, and the quantum yield is affected by competition between the nonradiative and radiative deactivations. The enhanced fluorescence of the molecular aggregates originates from the optically allowed S1–S0 transition together with the suppressed nonradiative deactivation via molecular stacking. These findings provide an in-depth understanding of the origin of the aggregation enhanced emission process, and may be applicable for the fine design of DSA based molecules with enhanced fluorescence and novel structures beyond DSA.
Co-reporter:Fengli Zhang, Yizeng Di, Yue Li, Qingkai Qi, Jingyu Qian, Xueqi Fu, Bin Xu, Wenjing Tian
Dyes and Pigments 2017 Volume 142(Volume 142) pp:
Publication Date(Web):1 July 2017
DOI:10.1016/j.dyepig.2017.04.004
•A series of highly efficient Far Red/Near-Infrared fluorescent compounds with aggregation-induced emission properties.•These compounds exhibit facile fabrication into uniform compound-loaded Pluronic F127 NPs.•These compounds are effective fluorescent probes for cancer cells with excellent properties.Organic fluorescent probes play an important role in modern biomedical research, such as biological sensing and imaging. However, the development of organic fluorophores with efficient aggregate state emissions expanded to the red to near-infrared region is still challenging. Here, we present a series of highly efficient Far Red/Near-Infrared (FR/NIR) fluorescent compounds with aggregation-induced emission (AIE) properties by attaching electron donor and accepter to tetraphenylethene (TPE) moieties through a simple synthesis method. These compounds exhibited the pronounced fluorescence enhancement in aggregate state, the red to near infrared emission, and can be facilely fabricated into uniform compounds-loaded Pluronic F127 NPs. The emission maximum of the NPs fabricated by the self-assembly method is in the range of 550–850 nm and the highest fluorescent quantum yield can get to 15.2%. The biological imaging of NPs of compound 1 and 2 for A549 lung cancer cell indicates that these compounds are effective fluorescent probes for cancer cells with high specificity, high photostability and good fluorescence contrast.Download high-res image (218KB)Download full-size image
Co-reporter:Ke Ma, Hui Wang, Haolong Li, Bin Xu, Wenjing Tian
Sensors and Actuators B: Chemical 2017 Volume 253(Volume 253) pp:
Publication Date(Web):1 December 2017
DOI:10.1016/j.snb.2017.06.055
•A novel optical platform was constructed for SNP analysis based on label-free fluorophore and water-soluble carbon nanotubes.•The sensing mechanism was established by studying the supermolecular interactions of fluorophore, carbon nanotubes and DNA.•The SNP analysis in random DNA sequence can be realized by this label-free optical platform.We design a label-free optical platform for SNP detection by using aggregation-induced emission (AIE) active molecule DSAI as the probe and water-soluble carbon nanotubes as the selective platform via the fluorescent quenching effect. In the presence of DNA, DSAI molecules aggregate on DNA through the intercalation and the electrostatic interaction as well as the hydrophobic interaction, resulting in the strong fluorescence in the solution. In order to distinguish the wild-DNA from the single nucleotide mutated-DNA, we induce the water-soluble carbon nanotubes as the effective fluorescent quenching material. The interactions between DSAI and wild-DNA are rather strong, thus DSAI molecules cannot be hauled out from wild-DNA and the fluorescence stays still. While the interactions between DSAI and single nucleotide mutated-DNA are relatively weak, and several DSAI molecules can be hauled out from the single nucleotide mutated-DNA by the water-soluble carbon nanotubes through the strong electrostatic interaction, leading to the partial fluorescent quenching in the solution. Therefore, the detection of SNP in the random DNA sequence could be realized by using AIE probes and carbon nanotubes.Download high-res image (104KB)Download full-size image
Co-reporter:Lulin Yan, Yan Zhang, Bin Xu and Wenjing Tian
Nanoscale 2016 vol. 8(Issue 5) pp:2471-2487
Publication Date(Web):01 Oct 2015
DOI:10.1039/C5NR05051K
Fluorescent nanoparticles (FNPs) have recently attracted increasing attention in the biomedical field because of their unique optical properties, easy fabrication and outstanding performance in imaging. Compared with conventional molecular probes including small organic dyes and fluorescent proteins, FNPs based on aggregation-induced emission (AIE) fluorogens have shown significant advantages in tunable emission and brightness, good biocompatibility, superb photo- and physical stability, potential biodegradability and facile surface functionalization. In this review, we summarize the latest advances in the development of fluorescent nanoparticles based on AIE fluorogens including polymer nanoparticles and silica nanoparticles over the past few years, and the various biomedical applications based on these fluorescent nanoparticles are also elaborated.
Co-reporter:Jiaxing Song, Weidong Hu, Xiao-Feng Wang, Gang Chen, Wenjing Tian and Tsutomu Miyasaka
Journal of Materials Chemistry A 2016 vol. 4(Issue 21) pp:8435-8443
Publication Date(Web):26 Apr 2016
DOI:10.1039/C6TA01074A
Despite the potential of ZnO as the electron collection material for low-temperature processed perovskite solar cells (PSCs), previous investigations revealed that the CH3NH3PbI3-based perovskite rapidly decomposes on ZnO at elevated temperature through a deprotonation process (base-induced reaction) that reduces thermal stability. To solve this thermal instability issue and to further enhance the photovoltaic performance, we employed a (FA)-based perovskite, i.e., FAPbI3 as the light absorber in ZnO-based PSCs. The photovoltaic performance of the investigated FAPbI3 solar cells was clearly dependent on both the pre-heating of the PbI2 precursor and post-annealing of the FAPbI3 film in the solar cell fabrication procedure. The highest power conversion efficiency of up to 16.1% was achieved under AM 1.5 simulated sunlight illumination, in which the pre-heating and post-annealing temperatures were 100 °C and 145 °C, respectively. Importantly, the thermostability of the perovskite film on ZnO was substantially improved with FAPbI3 owing to basically the robust nature of FA compared with methylammonium (MA) in CH3NH3PbI3. Moreover, FAPbI3-based PSCs exhibited excellent photostability and small J–V hysteresis, which are all useful characteristics for further commercialization of low-temperature processed ZnO solar cells.
Co-reporter:Qingkai Qi, Yue Li, Xiaoyu Yan, Fengli Zhang, Shan Jiang, Jing Su, Bin Xu, Xueqi Fu, Liankun Sun and Wenjing Tian
Polymer Chemistry 2016 vol. 7(Issue 33) pp:5273-5280
Publication Date(Web):25 Jul 2016
DOI:10.1039/C6PY01072E
A novel amphiphilic copolymer consisting of tetraphenylethylene-oxazolidine (TPE-OX) as a pH-sensitive chromophore and poly(ethylene glycol) methyl ether methacrylate (PEGMA) as a water-soluble chain has been well designed and synthesized. A self-assembled polymeric micelle based on the copolymer exhibited clear dual-emission switching between cyan and red with a decrease of pH value in Tris-HCl buffer solution due to the extended conjugation and emerging intramolecular charge transfer effect when opening the spiro-ring of OX moiety. Fluorescence imaging of HepG2 cells stained by the polymeric micelle shows switched luminescence from cyan to red with high selectivity and contrast, indicating that the polymeric micelle was an effective probe for intracellular pH detection. Additionally, the red emission of the polymeric micelle in lysosomes can reversibly switch back to the original cyan emission in response to the two lysosomal activity inhibitors chloroquine and bafilomycin, which demonstrates that the polymeric micelle has potential applications in detecting the activity of lysosomal and further autophagy in cancer cells.
Co-reporter:Jiaxing Song, Enqiang Zheng, Xiao-Feng Wang, Wenjing Tian, Tsutomu Miyasaka
Solar Energy Materials and Solar Cells 2016 Volume 144() pp:623-630
Publication Date(Web):January 2016
DOI:10.1016/j.solmat.2015.09.054
•The first report on ZnO–SnO2 as electron collection layer for perovskite solar cell.•The ZnO–SnO2 electron collection layers are low-temperature-processed.•An optimal ZnO–SnO2 (2:1 weight ratio in solution) gives the relatively high PCE.•The ZnO–SnO2 thin films exhibit better thermal stability of CH3NH3PbI3.•The PCE of the optimized device was further improved by introducing the Al2O3 layer.Electron collection layer (ECL) is one of the most important fundamentals to determine the power conversion efficiency (PCE) in organometal halide-based perovskite solar cells (PSCs). Herein, we prepared ZnO–SnO2 nanocomposites with different Zn/Sn ratios at low temperature as ECLs for CH3NH3PbI3-based planar-structured PSCs. ZnO–SnO2 nanocomposite with the optimal ~89 mol% of the ZnO content gives higher PCE than the ZnO for the best fabricated PSC. The photoluminescence spectroscopies measured in both steady and transient states and the electrochemical impedance spectroscopy were carried out to characterize the interface of CH3NH3PbI3 and different ECLs, namely ZnO, ZnO–SnO2 composite, and SnO2. The high PCE of PSCs based on the ZnO–SnO2 nanocomposite ECL was thus attributed to joint contributions of the high charge extraction efficiency and large charge recombination resistance both on the CH3NH3PbI3/ECL interface. The thermal stability of CH3NH3PbI3 absorber and the device stability of the corresponding PSC are both dependent on the ECLs in the order: SnO2>ZnO–SnO2 >ZnO, suggesting that the hydroxyl-induced degradation of CH3NH3PbI3 may be predominant in the ambient air environment in the initial ~700 h. The PCE of the optimized device was further improved to 15.2% by introducing the low-temperature processable Al2O3 as a capping layer to the ZnO–SnO2 composite.Download high-res image (239KB)Download full-size image
Co-reporter:Jingyu Qian, Bin Xu, Wenjing Tian
Organic Electronics 2016 Volume 37() pp:61-73
Publication Date(Web):October 2016
DOI:10.1016/j.orgel.2016.05.046
•The enhanced exchange-correlation energy in halogen decreases the bandgap and increases the PCE of perovskites.•Ge perovskites possess a similar absorption spectrum and carrier transport properties with Pb perovskites.•The theoretical PCE of Ge perovskites is close to that of Pb perovskites, and a little higher than Sn perovskites.Solar cells based on halide perovskites have recently been attractive due to their excellent power conversion efficiency (PCE), lower cost and simple manufacture. Here, a series of halide perovskites (ABX3: A = CH3NH3, CH(NH2)2, Cs, Rb; B = Pb, Sn, Ge; X = I, Br, Cl, F) were investigated by Density Functional Theory (DFT) calculations, together with Shockley-Queisser Maximum Solar Cell Efficiency (S-Q) and Spectroscopic Limited Maximum Efficiency (SLME) mathematical models. The results indicate that: the electronic structure of germanium perovskites bears a close similarity to that of lead perovskites with a small energy difference between the nonbonding orbital and antibonding orbitals, but with a large energy difference comparing with that of tin perovskites (0.6–1.7 eV for CsGeI3 at Z point of the Brillouin zone, 0.7–1.4 eV for CH3NH3PbI3 and 1.4–2.2 eV for CH3NH3SnI3 at R point of the Brillouin zone), which is attributable to the atomic level, where the 4s orbital energy of Ge (−11.5 eV) is close to the 6s orbital energy of Pb (−11.6 eV), but the 5s orbital energy of Sn (−10.1 eV) is significantly high. Therefore, germanium perovskites possess as high absorption coefficient around solar spectrum as lead perovskites, while tin perovskites only have low absorption coefficient, which makes the short-circuit current of CsGeI3 and CH3NH3PbI3 (0.017 Acm−2 and 0.016 Acm−2, simulated by SLME with a 200 nm absorber under AM1.5G) are higher than that of CH3NH3SnI3 (0.015 Acm−2) even if the bandgap of CsGeI3 and CH3NH3PbI3 (1.51 eV and 1.55 eV) are larger than that of CH3NH3SnI3 (1.21 eV). Meanwhile, the effective mass of electrons and holes are approximate for germanium perovskites and lead perovskites (0.14:0.19 for CsGeI3 and 0.12:0.12 for CH3NH3PbI3), indicating a balanced electrons and holes transport, whereas the electrons transport is much slower than the holes transport for tin perovskites due to the effective mass of electron is much larger than that of hole (0.17:0.04 for CH3NH3SnI3). As a result, the PCE of CsGeI3 (27.9%) and CH3NH3PbI3 (26.7%) is higher than that of CH3NH3SnI3 (19.9%).
Co-reporter:Yang Liu, Yajun Gao, Bin Xu, Paul H.M. van Loosdrecht, Wenjing Tian
Organic Electronics 2016 Volume 38() pp:8-14
Publication Date(Web):November 2016
DOI:10.1016/j.orgel.2016.07.018
•The dependence of the photoexcitation density, PC61BM composition, thermal annealing and thickness on Trap-limited bimolecular recombination has been investigated by photo-CELIV method in P3HT and PC61BM blend films.•The trap-limited bimolecular recombination is strongly affected by the distribution of the density of trap state (trap DOS).•The higher trap-limited bimolecular recombination rate means the trap DOS centered at lower energy which is beneficial to the releasing of trapped charge carriers, and leading to better charge carrier transportation.Trap-limited bimolecular recombination in poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) blend films has been investigated by using photo-induced charge extraction by linearly increasing voltage (photo-CELIV) method. The bimolecular recombination rate is strongly dependent on the photoexcitation density, the PC61BM composition and the thermal annealing process, but it slightly depends on the thickness of the blend film. The results show that the trap-limited bimolecular recombination is strongly affected by the distribution of the density of trap state (trap DOS). The higher trap-limited bimolecular recombination rate means the trap DOS centered at lower energy which is beneficial to charge carriers transportation, due to the lower activation energy and faster release rate. On the other hand, the trap-limited bimolecular recombination rate is mainly controlled by the slower species of charge carriers in the blend film when the transport of electrons and holes are strongly unbalanced, and the recombination rate will increase when the transport of electrons and holes becomes more balanced.
Co-reporter:Qing Zhao;Jing-yu Qian;Ying Liang;Zhi-cheng Zhong
Chinese Journal of Polymer Science 2016 Volume 34( Issue 1) pp:34-43
Publication Date(Web):2016 January
DOI:10.1007/s10118-016-1738-z
In this article, we designed and synthesized a series of 5-(2,6-dimethyl-4H-pyran-4-ylidene)-1,3-diethyl-2-thioxodihydropyrimidine- 4,6(1H, 5H)-dione (PD) unit based polymers (PFTDT, CZTDT, PHTDT and THTDT) for the first time. In these polymers, fluorene, 2,7-carbazole, phenothiazine and thiophene are employed as electron-donating groups and PD as electron-withdrawing group. TGA measurements demonstrated that these polymers possess good thermal stability (all above 377 °C). Very broad absorption spectrum was also obtained from the polymer THTDT (300–850 nm). CV characterization found that these polymers owned low highest occupied molecular orbital (HOMO) energy levels (–5.39 eV for THTDT,–5.49 eV for CZTDT and–5.78 eV for PFTDT) except for PHTDT (–5.17 eV). The geometry and electronic properties of PFTDT, CZTDT, PHTDT and THTDT were investigated by means of theoretical calculation. All the above advantages demonstrate that PD based polymers could be candidates for electronic devices.
Co-reporter:Qingkai Qi;Jingyu Qian;Xiao Tan;Jibo Zhang;Lijuan Wang;Bin Xu;Bo Zou
Advanced Functional Materials 2015 Volume 25( Issue 26) pp:4005-4010
Publication Date(Web):
DOI:10.1002/adfm.201501224
The molecular crystals of acridonyl-tetraphenylethene (AD-TPE) exhibit an intriguing turn-on and color-tuned luminescence in response to mechanical grinding and hydrostatic compression. On the basis of in-depth experimental and computational studies, it is hypothesized that the origin of the piezochromic behavior from the D-phase to the B-phase is the change of the intramolecular geometrical conformation, especially for the torsion angle between the TPE and AD moiety. The different molecular conformation in the two distinctive solid phases causes the substantial switching of the intramolecular charge transfer (ICT) process, which can be directly correlated with the subsequent fluorescence from locally excited (LE) state and ICT state in both phases. The AD-TPE molecular system presents a very rare example of high-contrast reversible fluorescence tuning driven by a switching of the excited state in the solid state under the mechanical stimuli, and thus provides a novel mechanism of the piezochromic behavior.
Co-reporter:Jiaxing Song, Enqiang Zheng, Ji Bian, Xiao-Feng Wang, Wenjing Tian, Yoshitaka Sanehira and Tsutomu Miyasaka
Journal of Materials Chemistry A 2015 vol. 3(Issue 20) pp:10837-10844
Publication Date(Web):09 Apr 2015
DOI:10.1039/C5TA01207D
We demonstrated SnO2 films prepared by sinter-less spin-coating processes as an electron selective contact for CH3NH3PbI3-based planar-heterojunction perovskite solar cells (PSCs). A modified sequential deposition method, in which the grain size of PbI2 precursors was controlled by an equivalent solvent vapor annealing (SVA) process, was used to prepare the perovskite layer on SnO2. With this SVA process, the remnant PbI2 nanocrystals can stably occur at the interface of CH3NH3PbI3/SnO2 to carry out a passivation effect. The photovoltaic performance of SnO2-based PSCs is dependent on both the SVA time and the thickness of the perovskite layer. The optimized PSC device achieves the best power conversion efficiency of up to 13% under the AM 1.5 simulated sunlight illumination, which is highly durable over 30 days of storage time with exposure to the ambient air environment.
Co-reporter:Yang Liu, Roderick. C. I. MacKenzie, Bin Xu, Yajun Gao, Miquel Gimeno-Fabra, David Grant, Paul. H. M. van Loosdrecht and Wenjing Tian
Journal of Materials Chemistry A 2015 vol. 3(Issue 47) pp:12260-12266
Publication Date(Web):10 Nov 2015
DOI:10.1039/C5TC02678D
Recently, Gao et al. reported being able to measure significant quantities of photogenerated charge up to one hour after it had been generated in an organic semiconductor device. The aim of this paper is twofold; (a) to provide conclusive experimental evidence to support the picture of device operation; and (b) to understand and demonstrate how changes to the device structure and materials can be used to tune the charge carrier lifetime. By tuning both the materials used, and the device structure we are able to observe a charge carrier life time of over 2 hours and still extract significant amounts of charge from the device after 5 hours. This is achieved by engineering the band structure of the device to control the spatial overlap of the stored photoexcited electron and hole populations and thus the recombination rate. By performing lifetime measurements as a function of charge carrier density and applied voltage we find the recombination rate has a 0th order dependence on carrier density, and elucidate the mechanisms responsible for these long charge carrier life times. This work is of technological significance for the development of organic electronic high sensitivity photodetectors and memory elements.
Co-reporter:Shiyu Yao, Zhaolai Chen, Fenghong Li, Bin Xu, Jiaxing Song, Lulin Yan, Gan Jin, Shanpeng Wen, Chen Wang, Bai Yang, and Wenjing Tian
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 13) pp:7146
Publication Date(Web):March 17, 2015
DOI:10.1021/am508985q
Without using any environmentally hazardous organic solution, we fabricated hybrid solar cells (HSCs) based on the aqueous-solution-processed poly(3-hexylthiophene) (P3HT) dots and CdTe nanocrystals (NCs). As a novel aqueous donor material, the P3HT dots are prepared through a reprecipitation method and present an average diameter of 2.09 nm. When the P3HT dots are mixed with the aqueous CdTe NCs, the dependence of the device performance on the donor–acceptor ratio shows that the optimized ratio is 1:24. Specifically, the dependence of the device performance on the active-layer thermal annealing conditions is investigated. As a result, the optimized annealing temperature is 265 °C, and the incorporation of P3HT dots as donor materials successfully reduced the annealing time from 1 h to 10 min. In addition, the transmission electron microscopy and atomic force microscopy measurements demonstrate that the size of the CdTe NCs increased as the annealing time increased, and the annealing process facilitates the formation of a smoother interpenetrating network in the active layer. Therefore, charge separation and transport in the P3HT dots:CdTe NCs layer are more efficient. Eventually, the P3HT dots:CdTe NCs solar cells achieved 4.32% power conversion efficiency. The polymer dots and CdTe NCs based aqueous-solution-processed HSCs provide an effective way to avoid a long-time thermal annealing process of the P3HT dots:CdTe NCs layer and largely broaden the donor materials for aqueous HSCs.Keywords: aqueous-solution-processed; hybrid solar cells; inorganic nanocrystals; polymer dots
Co-reporter:Enqiang Zheng, Xiao-Feng Wang, Jiaxing Song, Lulin Yan, Wenjing Tian, and Tsutomu Miyasaka
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 32) pp:18156
Publication Date(Web):July 29, 2015
DOI:10.1021/acsami.5b05787
A two-step sequential deposition method has been extensively employed to prepare the CH3NH3PbI3 active layer from the PbI2 precursor in perovskite solar cells (PSCs). The variation of the photovoltaic performance of PSCs made by this method was always attributed to different dipping times that induce complete/incomplete conversion of PbI2 into CH3NH3PbI3. To solve this issue, we employed a solvent vapor annealing (SVA) method to prepare PbI2 crystallites with large grain size for preparation of high quality perovskite. With this method, the increased PbI2 dipping time in CH3NH3I solution was found to reduce the photovoltaic performance of resulting PSCs without a significant change in PbI2/CH3NH3PbI3 contents in the perovskite films. We attribute this abnormal reduction of the photovoltaic performance to intercalation/deintercalation of the PbI2 core with a CH3NH3PbI3 shell, which causes the doping effect on both the PbI2 and CH3NH3PbI3 crystal lattices and the formation of a CH3NH3PbI3 capping layer on the surface, as revealed by UV–vis absorption, X-ray diffraction, FT-IR, and scanning electron microscope measurements. Based on our findings, a multistep dipping-drying process was employed as an alternative method to improve the crystalline quality. The method achieved power conversion efficiency up to 11.4% for the compact layer free PSC sharing a simple device structure of ITO/perovskite/spiro-OMeTAD/Ag.Keywords: compact layer free; low-temperature-processed device; PbI2 intercalation; perovskite solar cells; solvent vapor annealing
Co-reporter:Suqian Ma;Jibo Zhang;Jingyu Qian;Jinlong Chen;Bin Xu
Advanced Optical Materials 2015 Volume 3( Issue 6) pp:763-768
Publication Date(Web):
DOI:10.1002/adom.201400572
Co-reporter:Yajun Gao;Roderick C. I. MacKenzie;Yang Liu;Bin Xu;Paul H. M. van Loosdrecht
Advanced Materials Interfaces 2015 Volume 2( Issue 4) pp:
Publication Date(Web):
DOI:10.1002/admi.201400555
Co-reporter:Yan Zhang, Kaiwen Chang, Bin Xu, Jinlong Chen, Lulin Yan, Suqian Ma, Changfeng Wu and Wenjing Tian
RSC Advances 2015 vol. 5(Issue 46) pp:36837-36844
Publication Date(Web):14 Apr 2015
DOI:10.1039/C5RA04669F
Near-infrared emissive organic dots with a high fluorescence quantum efficiency (AEE dots) are prepared by using an amphiphilic polymer poly(styrene-co-maleic anhydride) (PSMA) as the co-encapsulation matrix and a novel small molecule fluorogen (DPPBPA) with high near-infrared emission as the core. The PSMA dots show small particle size of about 20 nm, a large Stokes shift of 304 nm and really high fluorescence quantum efficiency of 20%. The streptavidin-dots are obtained by conjugating streptavidin to carboxyl groups on the surface of PSMA dots. These streptavidin-dots can effectively and specifically label the target cell without any nonspecific binding, such as MCF-7 cells. Together with the negligible cytotoxicity, the near-infrared emissive AEE dots are promising red fluorescent probes for future bioimaging applications.
Co-reporter:Qing Guo, Lijuan Wang, Fuquan Bai, Yuanfei Jiang, Jing Guo, Bin Xu and Wenjing Tian
RSC Advances 2015 vol. 5(Issue 24) pp:18875-18880
Publication Date(Web):09 Feb 2015
DOI:10.1039/C4RA14274H
The charge transport properties of three crystalline polymorphs (α, β and γ) of 9,10-bis((E)-2-(pyrid-2-yl)vinyl)anthracene (BP2VA) were investigated at the first-principle level using Density Functional Theory (DFT) method based on Marcus theory, as well as the hybrid quantum mechanical and molecular mechanical (QM/MM) method. The polymorphism dependent charge transport property was explored by the calculation and analysis of the reorganization energy, the transfer integral, as well as the charge carrier mobilities of three different crystalline polymorphs. The results show that (1) β-BP2VA has the highest charge carrier mobility (for hole is 0.988 cm2 V−1 s−1 and for electron is 0.053 cm2 V−1 s−1) among the three crystalline polymorphs. (2) Comparison of the reorganization energy between individual molecule in gas-phase and embedded molecule when considering the steric effect of surrounding molecules suggests that the reorganization energy is dependent on intermolecular interaction for BP2VA. The calculated charge carrier mobilities are strongly dependent on the crystalline polymorphs. The enlightenment to us is that during the designing of optoelectronic materials with high charge mobility, we should pay attention to the molecular packing mode in the bulk material besides the molecular structure itself.
Co-reporter:Yajun Gao, Almantas Pivrikas, Bin Xu, Yang Liu, Weiqing Xu, Paul H.M. van Loosdrecht, Wenjing Tian
Synthetic Metals 2015 Volume 203() pp:187-191
Publication Date(Web):May 2015
DOI:10.1016/j.synthmet.2015.02.036
•We report the realization of charge selective CELIV for thin films.•The presence of double CELIV peaks indicates the involvement of deep trap states.•Photo-excited holes mainly populate shallow trap states.•Photo-excited electrons equally populate shallow and deep trap states.•Linear superposition does not hold when extract holes and electrons simultaneously.We report on the realization of charge selective CELIV (charge extraction by linearly increasing voltage) via the selective extraction of each charge carrier species in a SiO2 inserted MIS (metal-insulator-semiconductor) structure. The experiments are performed in a typical active layer of P3HT (poly (3-hexylthiophene)):PCBM (phenyl C61-butyric acid methyl ester) with a composition ratio of 1:1. The presence of double CELIV peaks indicates the involvement of deep trap states in the charge transport process. Furthermore the difference in excitation intensity dependence between photo-excited holes and electrons suggests a difference in population probabilities of electrons and holes for shallow and deep trap states. Charge selective CELIV experiments also show that the simultaneous extraction of holes and electrons is not a simple linear superposition of the cases where they are extracted separately, indicating that a fraction of photo-excited charges populating shallow trap states can escape from the device.
Co-reporter:Qing Guo;Lijuan Wang;Yuanfei Jiang;Jing Guo;Bin Xu
Chinese Journal of Chemistry 2015 Volume 33( Issue 8) pp:974-980
Publication Date(Web):
DOI:10.1002/cjoc.201500234
Abstract
Charge carrier mobility is one of the most significant properties for organic semiconductors. In this work, the electronic structures and charge transport properties of 9,10-bis((E)-2-(pyrid-n-yl)vinyl) (n=2, 3, 4) anthracene (BP2VA, BP3VA and BP4VA) were investigated via the analysis of the molecular geometry, the reorganization energy, the frontier orbital and density of state, as well as the electronic coupling and the charge mobility. The results indicated that the linkage between 9,10-divinyl anthracene unit and pyridine (ortho-, meta- and para-) influenced not only the intra-molecular conformation (i.e., the reorganization energies), but also the intermolecular interaction (i.e., transfer integrals), and finally the charge mobility of the molecules. It is also found that: (1) The calculated charge mobilties of holes are dozens of times higher than those of electrons for the three molecules. (2) The charge mobilities of hole and electron of the three molecules display the trend: μBP4VA>μBP2VA>μBP3VA, and the hole mobility of BP4VA is as high as ~1 cm2/(V·s).
Co-reporter:Leijing Liu;Hui Li;Shiyu Yao;Yingjin Wei
Journal of Materials Science 2015 Volume 50( Issue 1) pp:57-65
Publication Date(Web):2015 January
DOI:10.1007/s10853-014-8565-9
A novel solution-processable two-dimensional-conjugated organic small molecule based on triphenylamine (TPA) core, (E)-2-(3-(4-(bis(4-(3-hexyl-5-(7-(4-hexylthiophen-2-yl)benzo[c] [1,2,5] thiadiazol-4-yl)thiophen-2-yl)phenyl)amino)styryl)-5,5-dimethylcyclohex-2-en-1-ylidene)malononitrile (TPA-TBT), has been designed and synthesized by Knoevenagel reaction. Different from the linear or star-shaped TPA derivatives, in TPA-TBT, two arms of the TPA core are symmetrically connected with the acceptor segment 4,7-di(2-thienyl)-2,1,3-benzothiadiazole (DTBT), but the third arm is connected with a strong acceptor group, 2-(5,5-dimethylcyclohex-2-en-1-ylidene)malononitrile (DCM), connected through a trans double bond with the TPA core. TPA-TBT has a relatively low optical band gap (1.91 eV) and a deep highest occupied molecular orbital (HOMO) energy level (−5.53 eV). Bulk heterojunction photovoltaic devices were fabricated using TPA-TBT as the donor and (6,6)-phenyl C61-butyric acid methyl ester (PCBM) as the acceptor with the weight blend ratio of 2:1, 1:1, and 1:2. All the devices have a high open-circuit voltage (Voc) of about 0.9 eV. Device with 1:1 blend ratio and LiF modification to the cathode exhibited a better performance with a short circuit current (Jsc) of 4.86 mA cm−2 and a power conversion efficiency (PCE) of 1.13 %.
Co-reporter:Jinlong Chen, Suqian Ma, Jibo Zhang, Bao Li, Bin Xu, and Wenjing Tian
ACS Photonics 2015 Volume 2(Issue 2) pp:
Publication Date(Web):January 9, 2015
DOI:10.1021/ph5004384
A uniaxially oriented crystal based on 9,10-bis(2,2-di-p-tolylvinyl)anthracene (BDTVA) with an excellent waveguide and polarization performance has been prepared. The low loss coefficient (2.75 cm–1) and the high polarization contrast (0.72) may result from the uniaxially oriented packing and layer-by-layer molecular structure in the BDTVA crystal. Moreover, amplified spontaneous emission is observed from the BDTVA crystal with a low threshold of 265 μJ/cm2, and the gain coefficient is 52 cm–1 at the peak wavelength of 509 nm. These features indicate that the BDTVA crystal may be potentially applied in the field of optical waveguides and organic solid-state lasers.
Co-reporter:Dr. Qingkai Qi;Jingyu Qian;Suqian Ma;Dr. Bin Xu; Sean Xiao-An Zhang ; Wenjing Tian
Chemistry - A European Journal 2015 Volume 21( Issue 3) pp:1149-1155
Publication Date(Web):
DOI:10.1002/chem.201405426
Abstract
Two tetraphenylethene (TPE)-functionalized spiropyran (SP) molecules with very similar structure were designed and synthesized. The two molecules exhibit aggregation-induced emission (AIE) properties, as well as multistimuli-responsive color-changing properties, such as photochromism and acidchromism. The investigation of their different photochromic and acidchromic characteristics and dual-response fluorescent switch during isomerization indicated that the different link position between TPE and SP will significantly affect the extended π-conjugated system, resulting in completely different photochromic and acidchromic properties.
Co-reporter:Jibo Zhang;Bin Xu;Jinlong Chen;Suqian Ma;Yujie Dong;Lijuan Wang;Bao Li;Ling Ye
Advanced Materials 2014 Volume 26( Issue 5) pp:739-745
Publication Date(Web):
DOI:10.1002/adma.201303639
Co-reporter:Yan Zhang, Yujue Chen, Xing Li, Jibo Zhang, Jinlong Chen, Bin Xu, Xueqi Fu and Wenjing Tian
Polymer Chemistry 2014 vol. 5(Issue 12) pp:3824-3830
Publication Date(Web):14 Feb 2014
DOI:10.1039/C4PY00075G
Fluorescent block amphiphilic copolymers are one of the most important bioimaging materials which are highly desirable for early stage cancer diagnosis and treatment. However, sometimes the application of the fluorescent block copolymers is severely limited because of the aggregation-caused quenching (ACQ) effect. In this study, new aggregation induced emission polymer dots (AIE Pdots) were prepared through a self-assembly process by using an AIE-conjugated block copolymer containing an AIE fluorophore, 9,10-bis(4-hydroxystyryl)anthracene, hydrophobic poly(ε-caprolactone) segments, hydrophilic poly(ethylene glycol) segments and folate groups. The AIE Pdots are monodispersed in H2O with an average diameter of 15 nm, and possess strong emission and high solid state fluorescence quantum efficiency (Φ = 27.0%). Furthermore, the AIE Pdots show good stability and little toxicity to living cells and thus can be utilized for targeted HeLa cell imaging. Biological imaging investigation indicated that the folic acid functionalized AIE Pdots can be applied for targeted HeLa intracellular imaging.
Co-reporter:Xing Li, Ke Ma, Shoujun Zhu, Shiyu Yao, Zhaoyang Liu, Bin Xu, Bai Yang, and Wenjing Tian
Analytical Chemistry 2014 Volume 86(Issue 1) pp:298
Publication Date(Web):December 3, 2013
DOI:10.1021/ac403629t
Recently, a great variety of aggregation-induced emission (AIE)-active molecules has been utilized to design bioprobes for label-free fluorescent turn-on aptasensing with high sensitivity. However, due to nonspecific binding interaction between aptamer and AIE probe, these AIE-based aptasensors have nearly no selectivity, thereby significantly limiting the development. In this work, a 9,10-distyrylanthracene with two ammonium groups (DSAI) is synthesized as a novel AIE probe, and the fluorescent aptasensor based on DSAI and graphene oxide (GO) is developed for selective and sensitive sensing of targeted DNA and thrombin protein. Given its AIE property and high selectivity and sensitivity, this aptasensor can be also exploited to detect other targets.
Co-reporter:Bin Xu, Jibo Zhang, Honghua Fang, Suqian Ma, Qidai Chen, Hongbo Sun, Chan Im and Wenjing Tian
Polymer Chemistry 2014 vol. 5(Issue 2) pp:479-488
Publication Date(Web):28 Aug 2013
DOI:10.1039/C3PY00974B
Organic nonlinear optical materials combining high luminescence quantum yields and large two-photon absorption cross-sections are attractive for both fundamental research and practical applications, such as up-converted lasers and two-photon fluorescence microscopy. Herein, we reported a series of conjugated dendrimers (AnG0, AnG1, and AnG2) which showed weak emissions in dilute solution due to the twisted intramolecular charge transfer (TICT) and free intramolecular rotational motion. On the contrary, high luminescence quantum yields (up to 0.85) have been observed in the nanoaggregated and solid-state because of the restriction of intramolecular rotation (RIR) and the more planar conformation, which has been demonstrated by experimental and theoretical investigations. These dendrimers possess an obviously large intrinsic two-photon absorption cross-section (up to 5180 GM), which is enhanced with the increase of the generation number. Due to the high solid-state luminescence quantum yields, an intense two-photon excited fluorescence with a larger Stokes shift can be obtained from these dendrimers as nanoaggregates and thin films. Thus, these dendrimers successfully provide large two-photon action cross-sections in the nanoaggregated or solid-state and have the potential for nonlinear optical applications.
Co-reporter:Hongguang Lu, Xiaowei Zhao, Wenjing Tian, Qiusheng Wang and Ji Shi
RSC Advances 2014 vol. 4(Issue 35) pp:18460-18466
Publication Date(Web):07 Apr 2014
DOI:10.1039/C4RA01355G
In this work, fluorescence amplified organic nanoparticles (NPs) are synthesized by incorporation of the hydrophobic aggregation-induced emission (AIE) fluorophores, 9,10-bis(4-butoxystyryl) anthracene (BOSA) and/or bis(4-(N-(2-naphthyl)phenylamino)-phenyl)fumaronitrile (NPAPF), using biocompatible Pluronic F127–folic acid adduct (F127–FA) as the encapsulation matrix. The emission spectrum of BOSA donor overlaps well with the absorption spectrum of NPAPF acceptor, resulting in a 3.0-fold amplified NPAPF emission signal via fluorescence resonance energy transfer (FRET). The obtained BOSA–NPAPF co-loaded F127–FA nanoparticles (NPs) show a large Stokes shift of 245 nm, high water dispersibility, and low cytotoxicity. Application of these NPs for targeted cellular imaging is successfully demonstrated using folate receptor (FR)-overexpressed MCF-7 breast cancer cells as an example. Using the F127–FA as the encapsulation matrix, the folate-functionalized AIE NPs show bright fluorescence signals and specific targeting effect for FR-overexpressed cancer cells. These studies indicate that the F127–FA encapsulated AIE NPs are efficient fluorescent probes for biological imaging.
Co-reporter:Leijing Liu, Hui Li, Ji Bian, Jingyu Qian, Yingjin Wei, Jiyang Li and Wenjing Tian
New Journal of Chemistry 2014 vol. 38(Issue 10) pp:5009-5017
Publication Date(Web):04 Aug 2014
DOI:10.1039/C4NJ00814F
Two solution-processable two-dimensional conjugated organic small molecules based on triphenylamine (TPA) cores, TPA-BT-C8 and TPA-3Th, were designed and synthesized. As to TPA-BT-C8, two arms of the TPA core are symmetrically connected with a thiophene donor group and a benzothiadiazole acceptor group, while the third arm consists of a strong acceptor group of 2-(5,5-dimethylcyclohex-2-en-1-ylidene)malononitrile (DCM) connected through a trans double bond with the TPA core. For TPA-3Th, two arms of its TPA core are composed of only donor group, terthiophene, whereas the third arm consists of an acceptor group of cyano-n-octyl acetate connected through a trans double bond with the TPA core. The investigation indicated that TPA-BT-C8 has a lower energy band gap and wider absorption than TPA-3Th due to the strong intramolecular charge transfer effect in TPA-BT-C8. The two molecules have a deep highest occupied molecular orbital (HOMO) energy level. Bulk heterojunction photovoltaic devices were fabricated using TPA-BT-C8 or TPA-3Th as the donor and (6,6)-phenyl C61-butyric acid methyl ester (PCBM) as the acceptor. All the devices have a high open-circuit voltage (Voc) of about 0.9 eV. Devices based on TPA-BT-C8 have a much higher short circuit current (Jsc) (8.47 mA cm−2) and power conversion efficiency (PCE) (2.26%) than devices based on TPA-3Th (4.32 mA cm−2, 1.21%), resulting from wider solar light absorption of TPA-BT-C8 and better compatibility and film-formation ability of TPA-BT-C8 with PCBM than TPA-3Th. Incident photon-to-electron conversion efficiency (IPCE) spectra also confirmed that TPA-BT-C8 based devices have a wider and red-shifted response range than TPA-3Th based devices, which leads to a higher performance of the former devices.
Co-reporter:Lijuan Wang, Ping Li, Bin Xu, Houyu Zhang, Wenjing Tian
Organic Electronics 2014 Volume 15(Issue 10) pp:2476-2485
Publication Date(Web):October 2014
DOI:10.1016/j.orgel.2014.07.003
•The high charge mobility is due to the efficient overlaps of π-orbital and smaller π-stacking distance.•The hopping mechanism is suitable to TIPSAntBt, while the band mechanism play a key role in TIPSAntNa.•The introduced substituents contribute to different charge transport property in the two compounds.The charge transport property of two triisopropylsilylethynyl anthracene (TIPSAnt) derivatives TIPSAntBt and TIPSAntNa (bithiophene and naphthalene are introduced at the 2, 6-positions of the TIPSAnt core) were explored through quantum chemical method. To gain a better understanding of the substituent effect on the charge transport property, the results of the parent molecule TIPSAnt was also provided here for comparison. The substituent effect on the molecular geometry, reorganization energy, frontier orbitals, ionization potential (IP) and electronic affinity (EA), crystal property, transfer integrals and charge mobility, band structure and effective mass of the two compounds were investigated to establish the relationship between structures and properties. The introduced bulky TIPS groups made the two compounds adopt two-dimensional, face-to-face, π-stacking structures. The efficient overlaps of π-orbital and smaller π-stacking distance are proved to be the main reason for the high charge mobility of TIPSAntBt and TIPSAntNa. The hole mobilities of TIPSAntBt and TIPSAntNa are 0.88 and 3.60 cm2 V−1 s−1, respectively, which is well consistent with experiment values (0.2 and 3.7 cm2 V−1 s−1, respectively). For TIPSAntBt, the electron mobility (1.29 cm2 V−1 s−1) is a little higher than that of hole due to the more effective transfer integrals of electron. On the contrary, the hole mobility of TIPSAntNa is 20 times larger than that of electron because of the smaller reorganization energy and larger transfer integral of hole, indicating that TIPSAntNa could be used as p-type semiconductor. For TIPSAntBt, the transfer integral is smaller than the reorganization energy, so the hopping mechanism plays a key role in the charge transport property. While the bandwidths and effective mass of TIPSAntNa agreed well with the calculated transfer integrals and charge mobility results. The introduced small substituents to TIPSAnt core contributed to the dramatically different charge transport property from an n-type semiconductor of TIPSAntBt to p-type semiconductor of TIPSAntNa, which shed light on molecular design for an n-type semiconductor through simple chemical structural modification.
Co-reporter:Ke Ma, Xing Li, Bin Xu and Wenjing Tian
Analytical Methods 2014 vol. 6(Issue 7) pp:2338-2342
Publication Date(Web):08 Jan 2014
DOI:10.1039/C3AY42255K
A fluorescent turn-on approach for the sensitive and selective sensing of Hg2+ based on an aggregation-induced emission fluorescent molecule (DSA-T2) containing 9,10-distyrylanthracene as a fluorophore and thymine as a Hg2+ receptor, was developed. Under optimum conditions, a linear relationship (R2 = 0.9894) was obtained between the fluorescent intensity and the concentration of Hg2+ from 7 × 10−7 mol L−1 to 1 × 10−5 mol L−1. The theoretical detection limit of Hg2+ was evaluated to be 3.4 × 10−7 mol L−1. And the selectivity towards Hg2+ was good compared to other metal ions.
Co-reporter:Jinlong Chen, Suqian Ma, Jibo Zhang, Lijuan Wang, Ling Ye, Bao Li, Bin Xu, and Wenjing Tian
The Journal of Physical Chemistry Letters 2014 Volume 5(Issue 16) pp:2781-2784
Publication Date(Web):July 29, 2014
DOI:10.1021/jz501383d
A proton-triggered hypsochromic luminescent chromophore 1,1′-(2,5-distyryl-1,4-phenylene) dipiperidine (DPD) was designed and synthesized. Upon treatment by hydrochloric acid (HCl), the emission of DPD showed a large hypsochromic shift in both THF solution and microcrystals. Theoretical calculations and powder X-ray diffraction experiments reveal that the switchable emission of DPD originated from the change of the distribution and the spatial arrangement of the frontier molecular orbitals, and the different stacking modes of DPD in microcrystals also contribute to the switchable emission of DPD in aggregates.Keywords: acid/base stimuli; aggregating structure; frontier molecular orbitals; stacking mode; switchable fluorescent emission;
Co-reporter:Leijing Liu;Hui Li;Xiaoyu Zhang;Yingjin Wei;Jiyang Li
Journal of Materials Science 2014 Volume 49( Issue 15) pp:5279-5288
Publication Date(Web):2014 August
DOI:10.1007/s10853-014-8228-x
Two soluble acceptor–donor–acceptor (A–D–A) type organic small molecules, 2,2′-(5,5′-(1E,1′E)-2,2′-(benzo[c][1,2,5]thiadiazole-4,7-diyl)bis(ethene-2,1-diyl)bis(3,4-dihexylthiophene-5,2-diyl))bis(methan-1-yl-1-ylidene)dimalononitrile (BvT-DCN) and 2,2′-(3,3′-(1E,1′E)-2,2′-(5,5′-(1E,1′E)-2,2′-(benzo[c][1,2,5]thiadiazole-4,7-diyl)bis(ethene-2,1-diyl)bis(3,4-dihexylthiophene-5,2-diyl))bis(ethene-2,1-diyl)bis(5,5-dimethylcyclohex-2-ene-3-yl-1-ylidene))dimalononitrile (BT-C6), were synthesized by Knoevenagel condensation reaction based on benzothiadiazole, thiophene, and different terminal electron-withdrawing groups. The acceptor group benzothiadiazole and donor group thiophene inside the molecules are connected by all-trans double bonds, which ensures the benzothiadiazole and thiopene groups are in the same plane and makes the molecules have a relative narrow band gap and absorb sunlight in the long wavelength. The terminal electron-withdrawing groups, malononitrile and 2-(5,5-dimethylcyclohex-2-en-1-ylidene)malononitrile (DCM), are symmetrically introduced into the molecules, respectively, to tune the energy level and extend the absorption of the molecules. The UV–Vis absorption spectrum and cyclic voltammetry measurements indicated that BT-C6 has a lower energy band gap (1.60 eV) than BvT-DCN (1.71 eV), which arises from the stronger electron-withdrawing ability of DCM group in BT-C6 than that of malononitrile group in BvT-DCN. And BvT-DCN and BT-C6 have nearly the same highest occupied molecular orbital energy level, −5.74 eV for BvT-DCN and −5.72 eV for BT-C6 due to the same electron–donor group of the two compounds. Bulk heterojunction photovoltaic devices were fabricated using BvT-DCN or BT-C6 as donor and (6,6)-phenyl C61-butyric acid methyl ester as acceptor. The device based on BT-C6 has a higher (~8 times) short circuit current and power conversion efficiency than the device based on BvT-DCN, resulting from the wider solar light absorption of BT-C6 and smaller phase separation dimension of the active layer based on BT-C6.
Co-reporter:Yujie Dong, Jibo Zhang, Xiao Tan, Lijuan Wang, Jinlong Chen, Bao Li, Ling Ye, Bin Xu, Bo Zou and Wenjing Tian
Journal of Materials Chemistry A 2013 vol. 1(Issue 45) pp:7554-7559
Publication Date(Web):17 Sep 2013
DOI:10.1039/C3TC31553C
A novel divinylanthracene derivative 9,10-bis((E)-2-(pyridin-4-yl)vinyl)anthracene (BP4VA) was synthesized and its two polymorphs with different crystal structures were obtained. The introduction of pyridine in BP4VA leads to multi-stimuli responsive fluorescence. An investigation of the photophysical and stimuli responsive luminescent properties of BP4VA, including the piezochromism and protonation effect, demonstrates that the piezochromic luminescence originates from changes in the molecular aggregation state. Additionally, protonation–deprotonation of the pyridine moieties in BP4VA has a significant effect on the frontier molecular orbitals, resulting in distinct green and red emissions under acid and base stimuli. This study on BP4VA provides a comprehensive insight into the mechanisms within this type of stimuli-responsive luminescent material, and suggests that BP4VA may be a potential candidate for applications in sensing, detection and display devices with remarkable color-changing properties.
Co-reporter:Zilong Wang, Bin Xu, Lei Zhang, Jibo Zhang, Tenghe Ma, Jiabao Zhang, Xueqi Fu and Wenjing Tian
Nanoscale 2013 vol. 5(Issue 5) pp:2065-2072
Publication Date(Web):03 Jan 2013
DOI:10.1039/C2NR33685E
Fluorescent nanoparticles (FNPs) have been found to be useful as visualization tools for biological sensing, probing, imaging, and monitoring. Applied to targeted cancer cell imaging, FNPs are highly desirable for early stage cancer diagnosis and treatment. However, the light emission from most of the FNPs reported is severely limited because of the aggregation-caused quenching (ACQ) effect. Herein, we present highly emissive inorganic–organic nanoparticles with core–shell structures for targeted cancer cell imaging. Coated with a folate-functionalized silica shell, 9,10-distyrylanthracene (DSA) fluorogens with aggregation-induced emission (AIE) properties served as the fluorescent core, affording folate-functionalized fluorescent silica nanoparticles (FFSNPs) with a high fluorescence quantum yield (up to 20%). The FFSNPs are of small size (diameter ∼60 nm), monodispersed, stable in aqueous suspension, and pose little toxicity to living cells and thus can be utilized for targeted HeLa cell imaging. In addition, the FFSNPs are mesoporous and therefore can potentially be used as vehicles for controlled, externally activated release of anticancer drugs.
Co-reporter:Shiyu Yao, Pengfei Li, Ji Bian, Qingfeng Dong, Chan Im and Wenjing Tian
Journal of Materials Chemistry A 2013 vol. 1(Issue 37) pp:11443-11450
Publication Date(Web):15 Aug 2013
DOI:10.1039/C3TA11972F
A new quaternized ammonium polyfluorene polyelectrolyte poly[3,3′-(2-(3-hexyl-5-(7-(4-hexyl-5-methylthiophen-2-yl)benzo[c][1,2,5]thiadiazol-4-yl)thiophen-2-yl)-7-methyl-9H-fluorene-9,9-diyl)bis(N,N-dimethylpropan-1-amine)]dibromide (PFBTBr) is applied as the cathode interfacial layer of a polymer solar cell based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PC61BM). Electrostatic force microscopy (EFM) measurements of PFBTBr layers demonstrate the formation of the interfacial dipole between the active layer and the cathode by inserting a PFBTBr interfacial layer. Atomic force microscopy (AFM) measurements of PFBTBr layers with varied concentrations show that the morphology of the PFBTBr layer plays a direct, important role in the contact quality between the active layer and the PFBTBr interfacial layer, which can strongly affect the performance of devices. X-ray photoelectron spectroscopy measurements (XPS) indicate that PFBTBr may serve as a protective agent for the active layer against Al-induced degradation, since it prevents hot aluminum atoms from diffusing into the active layer. The power conversion efficiency (PCE) of the PSCs with the PFBTBr layer reaches 3.9% under the illumination of AM 1.5G, 100 mW cm−2, which is 1.6 times higher in comparison with that (2.4%) of the device without the PFBTBr layer. The significant increase in efficiency and easy utilization indicate that this interfacial material has promising and practical application prospects.
Co-reporter:Lijuan Wang, Bin Xu, Jibo Zhang, Yujie Dong, Shanpeng Wen, Houyu Zhang and Wenjing Tian
Physical Chemistry Chemical Physics 2013 vol. 15(Issue 7) pp:2449-2458
Publication Date(Web):21 Nov 2012
DOI:10.1039/C2CP41876B
The electronic structure and charge transport property of 9,10-distyrylanthracene (DSA) and its derivatives with high solid-state luminescent efficiency were investigated by using density functional theory (DFT). The impact of substituents on the optimized structure, reorganization energy, ionization potential (IP) and electronic affinity (EA), frontier orbitals, crystal packing, transfer integrals and charge mobility were explored based on Marcus theory. It was found that the hole mobility of DSA was 0.21 cm2 V−1 s−1 while the electron mobility was 0.026 cm2 V−1 s−1, which were relatively high due to the low reorganization energies and high transfer integrals. The calculated results showed that the charge transport property of these compounds can be significantly tuned via introducing different substituents to DSA. When one electron-withdrawing group (cyano group) was introduced into DSA, DSA–CN exhibited hole mobility of 0.14 cm2 V−1 s−1 which was on the same order of that of DSA. However, the electron mobility of DSA–CN decreased to 8.14 × 10−4 cm2 V−1 s−1 due to the relatively large reorganization energy and disadvantageous transfer integral. The effect of electron-donating substituents was investigated by introducing methoxy group and tertiary butyl into DSA. DSA–OCH3 and DSA–TBU showed much lower charge mobility than DSA resulting from the steric hindrance of substituents. On the other hand, both of them exhibited balanced transport properties (for DSA–OCH3, the hole and electron mobility was 0.0026 and 0.0027 cm2 V−1 s−1; for DSA–TBU, the hole and electron mobility was 0.045 and 0.012 cm2 V−1 s−1) because of their similar transfer integrals for both hole and electron. DSA and its derivatives were supposed to be one of the most excellent emissive materials for organic electroluminescent applications because of their high charge mobility and high solid-state luminescent efficiency.
Co-reporter:Weidong Cheng, Zhenghui Wu, Shanpeng Wen, Bin Xu, Hui Li, Furong Zhu, Wenjing Tian
Organic Electronics 2013 Volume 14(Issue 9) pp:2124-2131
Publication Date(Web):September 2013
DOI:10.1016/j.orgel.2013.05.015
•We have synthesized two new D–A conjugated copolymers.•The polymers contain benzo[1,2-b:4,5-b′]dithiophene unit and tetrazine unit.•Deep HOMO energy level was favor for Voc.•BHJ PSCs reached PCE of 5.12% and 5.0%, with high Voc of 1.01 V and 0.93 V.Two new low band gap conjugated polymers containing a benzo[1,2-b:4,5-b′]dithiophene donor unit and a tetrazine acceptor unit were synthesized by Stille cross-coupling polymerization. The structural and thermal properties of copolymers were characterized using nuclear magnetic resonance, gel permeation chromatography and thermogravimetric analysis. The results show that the donor–acceptor copolymers thus developed have good thermal stability with decomposition temperature of 294 °C and 305 °C. Cyclic voltammetric study revealed that the copolymers possess a deep-lying highest occupied molecular orbital energy level, which is desired for high open circuit voltage polymer solar cells (PSCs) and is also favorable for stable device operation in air. Bulk-heterojunction PSCs based on blend of low band gap copolymers: [6,6]-phenyl-C71-butyric acid methyl ester on indium tin oxide/glass substrates were fabricated. This work yielded a promising power conversion efficiency of >5.0%, with a high open circuit voltage of ∼1.0 V, measured under air mass 1.5 global irradiation of 100 mW/cm2.Graphical abstract
Co-reporter:Zhaoyang Liu, Xiao-Feng Wang, Zhongqiang Wang, Haruhiko Ojima, Ziruo Hong, Wenjing Tian, Junji Kido
Organic Electronics 2013 Volume 14(Issue 9) pp:2210-2215
Publication Date(Web):September 2013
DOI:10.1016/j.orgel.2013.05.029
•We use DSSC dye as electron donor in organic photovoltaics and receive high photovoltaic performance.•This is the first time that organic dye with carboxyl group was used for evaporated device.•The highest PCE of up to 4.5% was achieved under air mass AM 1.5G solar illumination.We demonstrated the use of an asymmetrical donor–acceptor-type indoline dye—D131, developed for dye-sensitized solar cells, as an electron donor and fullerene C70 as an electron acceptor for thermal co-evaporated bulk-heterojunction organic solar cells (OSCs). In spite of the presence of intermolecular hydrogen bonds among D131 molecules, they can be thermally evaporated in high vacuum at a relatively low temperature of 220 °C. The blend ratio and thickness of the active layer of D131/C70 blend films in OSCs were optimized to achieve a maximum power-conversion efficiency of 4.5% with a short-circuit current of 9.1 mA cm−2, an open-circuit voltage of 0.89 V, and a fill factor of 0.56 under AM 1.5G solar illumination (100 mW cm−2), which is the best value reported so far for OSCs based on indoline-based donor materials.Graphical abstract
Co-reporter:Weidong Cheng, Shiyu Yao, Shanpeng Wen, Pengfei Li, Hui Li, Lijuan Wang, Long Yan, Jinlong Chen, Jibo Zhang and Wenjing Tian
Polymer Journal 2013 45(10) pp:1072-1080
Publication Date(Web):March 27, 2013
DOI:10.1038/pj.2013.36
Three novel conjugated copolymers containing a coplanar bithiophenevinyl-(2-pyran-4-ylidenemalononitrile) unit linked with different electron-donating moieties by a double bond were synthesized via Heck polycondensation reactions and characterized using nuclear magnetic resonance, gel permeation chromatography and elemental analysis. Thermogravimetric analysis of the copolymers revealed that they have good thermal stability, with a decomposition temperature >330 °C. By eliminating torsional interactions between donor and acceptor units, combination by double bonds resulted in an enhancement of the conjugated length, extension of the absorption spectral range and a low band gap of the polymers. Cyclic voltammetry measurements suggest that the highest occupied molecular orbital and the lowest unoccupied molecular orbital energy levels of the copolymers can be fine-tuned by introducing donor units with different electron-donating ability. Bulk-heterojunction photovoltaic cells were fabricated with the copolymers as the donors and (6,6)-phenyl C71-butyric acid methyl ester as the acceptor. The cells based on the three copolymers exhibited power-conversion efficiencies of 0.36, 0.41 and 0.47% under one sun of air mass 1.5 solar simulator illumination (100 mV cm−2).
Co-reporter:Leijing Liu;Qing Guo;Jiyang Li;Bin Yao
Chinese Journal of Chemistry 2013 Volume 31( Issue 4) pp:456-464
Publication Date(Web):
DOI:10.1002/cjoc.201201197
Abstract
Four new star-shaped π-conjugated oligomers (TPA-CZ3, TPA-TPA3, TPA-PTZ3 and TPA-BT3) with triphenylamine as a core and different electron-donating ability groups, carbazole, triphenylamine, phenothiazine and bithiophene, as peripheral units have been designed and synthesized via the Heck reaction. These oligomers show good solubility in common organic solvents. Their photophysical, electrochemical, electronic structure and charge transfer properties between these star-shaped π-conjugated oligomers and N,N′-bis(1-ethylpropyl)-3,4:9,10-perylene bis(tetracarboxyl diimide) (EP-PDI) have been investigated by UV-vis absorption spectra, photoluminescence (PL) spectra, cyclic voltammetry (CV) measurement, theoretical calculations and fluorescence quenching. The results show that the absorptions and fluorescences of TPA-CZ3, TPA-TPA3 and TPA-PTZ3 are red shifted with the electron-donating ability of the peripheral unit increasing from carbazole to triphenylamine and phenothiazine. In addition, although the bithiophene group has a weaker electron-donating ability than carbazole, triphenylamine and phenothiazine, the absorption and fluorescence of TPA-BT3 have a red shift than those of TPA-CZ3, TPA-TPA3 and TPA-PTZ3 because TPA-BT3 has a longer conjugation length than TPA-CZ3, TPA-TPA3 and TPA-PTZ3. The triphenylamine core and the peripheral units can constitute a large conjugated structure. The fluorescence quenching properties indicate that efficient charge transfer can happen between the star-shaped oligomers and EP-PDI.
Co-reporter:Suqian Ma;Jibo Zhang;Jinlong Chen;Lijuan Wang;Bin Xu
Chinese Journal of Chemistry 2013 Volume 31( Issue 11) pp:1418-1422
Publication Date(Web):
DOI:10.1002/cjoc.201300583
Abstract
A novel organic fluorophor with high solid state luminescent efficiency based on 1,4-bis(2,2-di(pyridin-2-yl)vinyl)benzene (BDP2VB) was designed and synthesized. It emits faintly in solution, but becomes a strong emitter in the aggregate state, demonstrating its aggregation induced emission (AIE) property. According to the crystal structure analysis, J-type aggregation was formed in the packing mode of the molecule, which was demonstrated to be beneficial to gain high fluorescent quantum efficiency in solid state. Additionally, the emission color of BDP2VB can change dramatically in solid state as well as in solution by the protonation stimuli.
Co-reporter:Leijing Liu;Qing Guo;Jiyang Li;Bin Yao
Chinese Journal of Chemistry 2013 Volume 31( Issue 4) pp:
Publication Date(Web):
DOI:10.1002/cjoc.201390008
Co-reporter:Leijing Liu;Jianing Pei;Shanpeng Wen;Jiyang Li;Bin Yao
Macromolecular Chemistry and Physics 2013 Volume 214( Issue 16) pp:1836-1844
Publication Date(Web):
DOI:10.1002/macp.201300291
Co-reporter:Xing Li, Bin Xu, Hongguang Lu, Zilong Wang, Jibo Zhang, Yan Zhang, Yujie Dong, Ke Ma, Shanpeng Wen and Wenjing Tian
Analytical Methods 2013 vol. 5(Issue 2) pp:438-441
Publication Date(Web):21 Nov 2012
DOI:10.1039/C2AY26202A
A label-free fluorescence turn-on approach for the selective sensing of Pb2+ based on quaternary ammonium salt of 9,10-distyrylanthracene with aggregation-induced emission (AIE) property was developed through Pb2+-induced allosteric G-quadruplex (G4). The method is simple, easy to operate, cost-effective, and provides good sensitivity and selectivity.
Co-reporter:Qingkai Qi ; Jibo Zhang ; Bin Xu ; Bao Li ; Sean Xiao-An Zhang
The Journal of Physical Chemistry C 2013 Volume 117(Issue 47) pp:24997-25003
Publication Date(Web):November 7, 2013
DOI:10.1021/jp407965a
The mechanochromic property of tetrakis(4-(dimethylamino)phenyl)ethylene (TDMAPE) with natural propeller shape and nearly centrosymmetric structure was investigated. The destruction of the crystalline structure leads to the planarization of molecular conformation, which is considered as a possible reason for the red-shift of absorption and fluorescence spectra after grinding. And the polymorphism-dependent emissions of the two polymorphs of TDMAPE are mainly determined by the intramolecular conformation, which show the increased coplanarity or conjugation degree, ultimately leading to the bathochromic shift of the emissions.
Co-reporter:Jibo Zhang ; Bin Xu ; Jinlong Chen ; Lijuan Wang
The Journal of Physical Chemistry C 2013 Volume 117(Issue 44) pp:23117-23125
Publication Date(Web):September 30, 2013
DOI:10.1021/jp405664m
Two 9,10-divinylanthracene oligomers containing phenothiazines (AnPHZ2 and AnPHZ4) are synthesized, and their intramolecular charge transfer as well as aggregation-induced emission (AIE) properties are investigated. Both oligomers show typical AIE properties as well as solvent polarity dependent emission. Time-resolved fluorescence spectra revealed that the twisted intramolecular charge transfer state formed in polar solvents accounts for the weak emission with large Stokes shifts, and the interactions between solvent and solutes facilitate the nonradiative decay. The restriction of intramolecular torsion induced by supramolecular interactions in aggregates eliminates the charge transfer state, thus resulting in efficient AIE.
Co-reporter:ZiLong Wang;Ke Ma;Bin Xu;Xing Li
Science China Chemistry 2013 Volume 56( Issue 9) pp:1234-1238
Publication Date(Web):2013 September
DOI:10.1007/s11426-013-4917-6
A sulfonated 9,10-distyrylanthracene derivative with aggregation-induced emission (AIE) property is designed and synthesized. It shows a highly sensitive and selective fluorescence enhancement property for bovine serum albumin (BSA) protein detection and quantification. Analysis on the interaction between the probe molecule and BSA reveals the essential role of the hydrophobic cavities of the protein folding structure.
Co-reporter:JinLong Chen;SuQian Ma;Bin Xu;JiBo Zhang;YuJie Dong
Science Bulletin 2013 Volume 58( Issue 22) pp:2747-2752
Publication Date(Web):2013 August
DOI:10.1007/s11434-013-5897-9
Two 9,10-distyrylanthracene (DSA) derivatives CNDSA and t-BUDSA were designed and synthesized, and their photophysical properties and crystal structures were investigated. Compared to DSA, the maximum emission peaks of the two compounds showed red-shift not only in THF solution, but also in crystals, because the introduction of electron-withdrawing substituents to DSA leads to more dispersion of the electrons in the molecules. The two crystals of CNDSA and t-BUDSA show strong fluorescence with the efficiency ΦF of 45% and 33%, respectively, which may be resulted from no obvious π-π interactions between molecules inside the crystal due to the large distance between the two adjacent molecules and nearly no overlap between the central anthracene planes. The analysis of crystal structures of the two compounds indicated that the molecules are arranged in the same conformation and orientation in their crystals, i.e. uniaxially oriented packing crystal, because of the supramolecular interaction of CH/π in the two crystals and additional C-H…N interactions in CNDSA.
Co-reporter:Yujie Dong, Bin Xu, Jibo Zhang, Hongguang Lu, Shanpeng Wen, Feipeng Chen, Jiating He, Bao Li, Ling Ye and Wenjing Tian
CrystEngComm 2012 vol. 14(Issue 20) pp:6593-6598
Publication Date(Web):26 Jun 2012
DOI:10.1039/C2CE25276G
Three DSA (9,10-distyrylanthracene) derivatives, 9,10-bis(3,5-dimethylstyryl)anthracene (TMDSA), 9,10-bis(3,5-bis(trifluoromethyl)styryl)anthracene (TFMDSA) and 9,10-bis(3,5-difluorostyryl)anthracene (TFDSA) were synthesized and characterized. Here we report their crystal structures, structure-property relationships, and nanowire fabrication. The crystal structures indicate that the three compounds with varying substituents exhibit different molecular packing modes. In particular, introducing a F substituent to generate weak intermolecular C–H⋯F interactions benefits the formation of intermolecular π–π stacking in the TFMDSA and TFDSA crystals. Photophysical investigations and crystal structure analysis indicate that inhibition of vibrational relaxation in the aggregate state should be the origin for the high fluorescence and blueshift in crystals of our materials. By controlling the experimental conditions, TFDSA could easily achieve perfect regular 1D nanowires, in which the weak intermolecular C–H⋯F interaction together with effective π–π interaction play a significant role. High quantum efficiency (75% for TFDSA) and regular 1D nanowires suggest that this kind of material may have potential applications in optoelectronic device applications.
Co-reporter:Pengfei Li, Shanpeng Wen, Weidong Cheng, Jibo Zhang, Shiyu Yao, Bin Xu and Wenjing Tian
New Journal of Chemistry 2012 vol. 36(Issue 8) pp:1626-1633
Publication Date(Web):30 May 2012
DOI:10.1039/C2NJ40194K
A series of poly(p-phenylenevinylene) based polymers (MEH-OXD-PPVs) functionalized with Y-shaped double 1,3,4-oxadiazole-containing side chains were synthesized through a modified Gilch reaction. They are all soluble in common organic solvents such as chloroform, tetrahydronfuran and 1,1,2,2-tetrachloroethane. The chemical structures of MEH-OXD-PPVs were determined by 1H NMR, GPC and elemental analysis. Thermogravimetric analysis shows that they have good thermal stability with the decomposition temperature ranging from 312 °C to 326 °C. The absorption and fluorescence emission maxima of the polymers exhibit an appreciable blue-shift with the increase of oxadiazole-containing moieties. Electrochemical investigation shows that the HOMO energy levels of the polymers vary regularly with the change of content of oxadiazole-containing moieties. Additionally, by introducing more OXD-PV unit during copolymerization, the PL quantum efficiencies of the polymers are significantly enhanced compared to that of MEH-PPV. The successful manipulation of optical and electronic properties of the MEH-OXD-PPVs indicates an effective concept for developing PPV-based functional materials with tunable optoelectronic properties by changing the amount of electron-withdrawing oxadiazole-containing moieties.
Co-reporter:Guanjun Xiao, Qingfeng Dong, Yingnan Wang, Yongming Sui, Jiajia Ning, Zhaoyang Liu, Wenjing Tian, Bingbing Liu, Guangtian Zou and Bo Zou
RSC Advances 2012 vol. 2(Issue 1) pp:234-240
Publication Date(Web):03 Nov 2011
DOI:10.1039/C1RA00289A
In this paper, we introduce a facile and phosphine-free one-step solution method to synthesize size- and shape-controlled bismuth sulfide (Bi2S3) with hierarchical architectures. Changing variables, such as the reaction temperature, the ratio of precursors, and the concentration of oleic acid were observed to influence the resultant shape of Bi2S3 microstructures. For the formation of Bi2S3 hierarchical architectures, the crystal splitting growth mechanism played the dominant role. The absorption spectra were recorded at room temperature, which revealed that the obtained Bi2S3 product was a direct band gap semiconductor and the band gap Eg was estimated to be about 1.9 eV. Furthermore, the I–V characteristics of the Bi2S3-based device show a significant increase by ca. 1 order of magnitude compared with the dark state, indicating an enhanced conductivity and high sensitivity. The response and decay times are estimated to be about 0.5 and 0.8 s, respectively, which are short enough for it to be an excellent candidate for high-speed and high-sensitivity photodetectors or optical switches. Thus the Bi2S3 hierarchies as building blocks may offer the potential for monolithic, low-cost and large-scale integration with CMOS electronics.
Co-reporter:Zhaoyang Liu, Leijing Liu, Hui Li, Qingfeng Dong, Shiyu Yao, Arnold B. Kidd IV, Xiaoyu Zhang, Jiyang Li, Wenjing Tian
Solar Energy Materials and Solar Cells 2012 97() pp: 28-33
Publication Date(Web):
DOI:10.1016/j.solmat.2011.09.023
Co-reporter:Zaifang Li, Qingfeng Dong, Bin Xu, Weidong Cheng, Shiyu Yao, Xiaoyu Zhang, Shanpeng Wen, Hui Li, Yujie Dong, Wenjing Tian
Solar Energy Materials and Solar Cells 2012 98() pp: 343-350
Publication Date(Web):
DOI:10.1016/j.solmat.2011.10.035
Co-reporter:Shanpeng Wen, Qingfeng Dong, Weidong Cheng, Pengfei Li, Bin Xu, Wenjing Tian
Solar Energy Materials and Solar Cells 2012 100() pp: 239-245
Publication Date(Web):
DOI:10.1016/j.solmat.2012.01.025
Co-reporter:Qingfeng Dong, Weili Yu, Zaifang Li, Shiyu Yao, Xiaoyu Zhang, Bai Yang, Chan Im, Wenjing Tian
Solar Energy Materials and Solar Cells 2012 104() pp: 75-80
Publication Date(Web):
DOI:10.1016/j.solmat.2012.04.024
Co-reporter:Yujie Dong;Dr. Bin Xu;Jibo Zhang;Xiao Tan;Lijuan Wang;Jinlong Chen;Dr. Hongguang Lv;Dr. Shanpeng Wen;Dr. Bao Li;Dr. Ling Ye;Dr. Bo Zou;Dr. Wenjing Tian
Angewandte Chemie International Edition 2012 Volume 51( Issue 43) pp:10782-10785
Publication Date(Web):
DOI:10.1002/anie.201204660
Co-reporter:Shanpeng Wen;Weidong Cheng;Pengfei Li;Shiyu Yao;Bin Xu;Hui Li;Yajun Gao;Zilong Wang
Journal of Polymer Science Part A: Polymer Chemistry 2012 Volume 50( Issue 18) pp:3758-3766
Publication Date(Web):
DOI:10.1002/pola.26164
Abstract
Three donor–acceptor (D–A) 1,3-di(thien-2-yl)thieno [3,4-c]pyrrole-4,6-dione-based copolymers, poly{9,9-dioctylfluorene-2,7-diyl-alt-1,3-bis(4-hexylthien-2-yl)-5-octylthieno[3,4-c]pyrrole-4,6-dione}, poly{N-(1-octylnonyl)carbazole-2,7-diyl-alt-1,3-bis(4-hexylthien-2-yl)-5-octylthieno[3,4-c]pyrrole-4,6-dione}, and poly {4,8-bis(2-ethylhexyloxyl) benzo[1,2-b:3,4-b′]dithiophene-alt-1,3-bis(4-hexylthien-2-yl)-5-octylthieno[3,4-c] pyrrole-4,6-dione} were synthesized by Suzuki or Stille coupling reaction. By changing the donor segment, the bandgaps and energy levels of these copolymers could be finely tuned. Cyclic voltammetric study shows that the highest occupied molecular orbital (HOMO) energy levels of the three copolymers are deep-lying, which implies that these copolymers have good stability in the air and the relatively low HOMO energy level assures a higher open-circuit potential when they are used in photovoltaic cells. Bulk-heterojunction photovoltaic cells were fabricated with these polymers as the donors and PC71BM as the acceptor. The cells based on the three copolymers exhibited power conversion efficiencies of 0.22, 0.74, and 3.11% with large open-circuit potential of 1.01, 0.99, and 0.90 V under one sun of AM 1.5 solar simulator illumination (100 mW/cm2). © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Co-reporter:Bin Xu, Jiating He, Yujie Dong, Feipeng Chen, Weili Yu and Wenjing Tian
Chemical Communications 2011 vol. 47(Issue 23) pp:6602-6604
Publication Date(Web):16 May 2011
DOI:10.1039/C1CC11706H
Conjugated oligocarbazoles with a 9,10-divinylanthracene core have been synthesized, and exhibit the transition from aggregation-induced emission (AIE) to aggregation-induced emission enhancement (AIEE) behaviour with extending conjugation length; self-assembly of the Cz4 molecule affords nanorings with high fluorescent efficiency.
Co-reporter:Jianing Pei, Shanpeng Wen, Yinhua Zhou, Qingfeng Dong, Zhaoyang Liu, Jibo Zhang and Wenjing Tian
New Journal of Chemistry 2011 vol. 35(Issue 2) pp:385-393
Publication Date(Web):21 Oct 2010
DOI:10.1039/C0NJ00378F
A new low band gap copolymer containing dialkylfluorene and 4,7-dithienyl-2,1,3-benzothiadiazole (TBT), poly(fluorenevinylene-alt-4,7-dithienyl-2,1,3-benzothiadiazole) (PF-TBT) was synthesized by Heck cross-coupling polymerization. The copolymer is soluble in common organic solvents such as chloroform, tetrahydrofuran and chlorobenzene. The TGA result indicated that the copolymer possesses good thermal stability. The absorption, electrochemical and photovoltaic properties of PF-TBT were investigated and compared with those of poly(fluorenevinylene-alt-4,7-diphenyl-2,1,3-benzothiadiazole) (PF-DBT) whose structure is similar to PF-TBT. The copolymer exhibited a broad absorption band with an absorption edge close to 700 nm and an optical band gap of 1.82 eV. Cyclic voltammetry studies indicated that the relatively low HOMO energy level assured a higher open circuit voltage (Voc) when PF-TBT is used as the donor material in a photovoltaic cell. The bulk heterojunction (BHJ) solar cell using PF-TBT as the donor and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) as the acceptor with the structure of ITO/PEDOT:PSS/copolymer:PCBM/LiF/Al, exhibited a Voc of 0.86 V, short-circuit current density (Jsc) of 3.97 mA cm−2, fill factor (FF) of 0.35, and a power conversion efficiency (PCE) of 1.18% under one sun of AM 1.5 solar simulator illumination (100 mW cm−2).
Co-reporter:Qiang Li, Leijing Liu, Zhaoyang Liu, Zaifang Li, Weidong Cheng, Shanpeng Wen, Pengfei Li, Zijian Li, Wenjing Tian
Synthetic Metals 2011 Volume 161(9–10) pp:731-736
Publication Date(Web):May 2011
DOI:10.1016/j.synthmet.2011.01.022
A novel soluble conjugated donor–acceptor (D–A) copolymer, poly(2-(2-((E)-2(3,4-dihexyl-5-(7-methyl-9-octyl-9H-carbazole-2-yl)thiophene-2-yl)vinyl)-6((E)-2-(3,4-dihexyl-5-methylthiophen-2yl)vinyl-4H-pyran-4-ylidene)malononitrile) (CZPM), consisting of alternating 2,7-carbazole and (bithiophenevinyl)-(2-pyran-4-ylidenemalononitrile) (TVM) was synthesized by Suzuki coupling polymerization. The photophysical and photovoltaic properties of the copolymer were investigated. The UV–vis absorption spectrum and cyclic voltammetry measurements of CZPM film showed that the copolymer has a relatively low band gap (1.81 eV) and a deep highest occupied molecular orbital (HOMO) level (−5.55 eV). Bulk heterojunction photovoltaic devices were fabricated using CZPM as donor and (6,6)-phenyl C61-butyric acid methyl ester (PCBM) as acceptor with the weight blend ratio ranging from 1:1 to 1:4. The device with the blend ratio of 1:2 between CZPM and PCBM exhibited an open-circuit voltage (Voc) of 0.74 V and a power conversion efficiency (PCE) of 0.1% under simulated AM1.5 solar irradiation (100 mW/cm2). The relatively low conversion efficiency of the device is attributed to the ineffective exciton dissociation at the CZPM/PCBM interface and the imperfect film-forming property of the polymer resulting from the low molecular weight.Research highlights► A novel soluble conjugated donor-acceptor copolymer, CZPM, was synthesized. ► CZPM has a relatively low band gap of 1.81 eV. ► CZPM has a deep highest occupied molecular orbital level of −5.55 eV. ► The solar cell based on CZPM as donor exhibited a Voc of 0.74 V and a PCE of 0.1%. ► The low PCE is due to the ineffective exciton dissociation and the imperfect film.
Co-reporter:Shanpeng Wen;Jianing Pei;Pengfei Li;Yinhua Zhou;Weidong Cheng;Qingfeng Dong;Zaifang Li
Journal of Polymer Science Part A: Polymer Chemistry 2011 Volume 49( Issue 12) pp:2715-2724
Publication Date(Web):
DOI:10.1002/pola.24704
Abstract
Three novel low-bandgap copolymers containing alkylated 4,7-dithien-2-yl-2,1,3-benzothiadiazole (HBT) and different electron-rich functional groups (dialkylfluorene (PFV-HBT), dialkyloxyphenylene (PPV-HBT) and dialkylthiophene (PTV-HBT)) were prepared by Horner polycondensation reactions and characterized by 1H NMR, gel permeation chromatography, and elemental analysis. The alkyl side chain brings these polymeric materials good solubility in common organic solvents, which is critical for the manufacture of solar cells in a cost-effective manner. The copolymers exhibit low optical bandgap from 1.48 to 1.83 eV. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the copolymers were measured by cyclic voltammetry. Theoretical calculations revealed that the variation laws of HOMO and the LUMO energy levels are well consistent with cyclic voltammetry measurement. The bulk heterojunction photovoltaic devices with the structure of ITO/PEDOT-PSS/polymer:PCBM/LiF/Al were fabricated by using the three copolymers as the donor and (6,6)-phenyl-C61-butyric acid methyl ester (PCBM) as the acceptor in the active layer. The device based on PTV-HBT:PCBM (1:4 w/w) achieved a power conversion efficiency of 1.05% under the illumination of AM 1.5, 100 mW/cm2. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.
Co-reporter:Yaowen Li ; Bin Xu ; Hui Li ; Weidong Cheng ; Lili Xue ; Feipeng Chen ; Hongguang Lu
The Journal of Physical Chemistry C 2011 Volume 115(Issue 5) pp:2386-2397
Publication Date(Web):January 6, 2011
DOI:10.1021/jp1090872
A series of donor−acceptor (D−A) conjugated copolymers with benzo[1,2-b:4,5-b′]dithiophene (BDT) as donor and two different electron-accepting groups bithiophenevinyl-2-pyran-4-ylidenemalononitrile (TVM) and benzothiadiazole (BT) moieties as acceptors is designed and synthesized. The optical and electrochemical properties show that the band gaps of the copolymers are in the range of 1.70−1.84 eV, and the HOMO and LUMO energy levels can be tuned effectively by controlling the varied ratios between TVM and BT because of the change of the ICT interaction between donor and acceptor, the electron delocalization degree, and the electron cloud density distribution of the copolymers. Bulk heterojunction photovoltaic devices are fabricated by using the copolymers as donors and (6,6)-phenyl-C61-butyric acid methyl ester (PC61BM) or (6,6)-phenyl-C71-butyric acid methyl ester (PC71BM) as acceptors. The optimized photovoltaic performances show that the open-circuit voltage (Voc) was gradually increased from 0.7 to 0.94 V when decreasing the HOMO energy levels of copolymers, and the short-circuit current density (Jsc) is greatly improved by increasing the absorption spectrum in the visible region, increasing the hole mobility and optimizing the morphologies of blend films between copolymers and PCBM. The optimized photovoltaic performance with a Voc of 0.78 V, Jsc of 5.47 mA/cm2, fill factor (FF) of 0.40, and power conversion efficiency (PCE) of 1.67% under simulated AM 1.5 solar irradiation of 100 mW/cm2 is obtained by the copolymer PM50 (PM50:PC61BM, 1:3 w/w, in CB solution). This is due to its high hole mobility and interpenetrating network morphology of PM50:PC61BM blend film. The photovoltaic device based on PM50:PC71BM shows a Jsc of 8.32 mA/cm2 and a PCE of 2.89%.
Co-reporter:Zaifang Li, Qingfeng Dong, Bin Xu, Hui Li, Shanpeng Wen, Jianing Pei, Shiyu Yao, Hongguang Lu, Pengfei Li, Wenjing Tian
Solar Energy Materials and Solar Cells 2011 95(8) pp: 2272-2280
Publication Date(Web):
DOI:10.1016/j.solmat.2011.03.040
Co-reporter:Jianing Pei, Jinlong Tao, Yinhua Zhou, Qingfeng Dong, Zhaoyang Liu, Zaifang Li, Feipeng Chen, Jibo Zhang, Weiqing Xu, Wenjing Tian
Solar Energy Materials and Solar Cells 2011 95(12) pp: 3281-3286
Publication Date(Web):
DOI:10.1016/j.solmat.2011.07.007
Co-reporter:Bin Xu, Honghua Fang, Yujie Dong, Feipeng Chen, Qidai Chen, Hongbo Sun and Wenjing Tian
New Journal of Chemistry 2010 vol. 34(Issue 9) pp:1838-1842
Publication Date(Web):26 Jul 2010
DOI:10.1039/C0NJ00300J
Methyl-substituted 9,10-distyrylanthracene was synthesized by a simple Heck reaction and its photophysical properties investigated. Tight intermolecular stacking through supramolecular interactions in the crystal not only induced strong fluorescence emission with a high fluorescence efficiency of 35% but also conducted the formation of large size and high quality needle-like single crystals. Amplified spontaneous emission (ASE) with a low threshold value of 10 μJ pulse−1 was observed.
Co-reporter:Qingfeng Dong, Yinhua Zhou, Jianing Pei, Zhaoyang Liu, Yaowen Li, Shiyu Yao, Jibo Zhang, Wenjing Tian
Organic Electronics 2010 Volume 11(Issue 7) pp:1327-1331
Publication Date(Web):July 2010
DOI:10.1016/j.orgel.2010.04.012
Semi-transparent inverted polymer solar cells (PSCs) were fabricated by all-spin-coating vacuum-free process. An interfacial layer of poly(allylamine hydrochloride) and dextran (PAH-D) was introduced to modify the surface wettability of poly(3-hexylthiophene) (P3HT):[6,6]-phenyl C61-butyric acid methyl ester (PCBM) film for depositing aqueous-solution-processed poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) (CLEVIOS™ PH500) (PH500) anode as well as enhancing the adhesion and bonding strength between the active layer (P3HT:PCBM) and conducting polymer electrode (PH500). The photovoltaic performance of the semi-transparent PSCs under top and bottom illumination was investigated and the highest PCE of about 1.86% was achieved under simulated AM 1.5 illumination (100 mW/cm2) from the bottom side with a reflective white paper back side. The semi-transparent Cell A have the potential for use as energy-generating color window glasses as well as the subcell of tandem solar cells. The all-spin-coating vacuum-free processing provides a possibility of high-throughput all-solution-processed fabrication of PSCs by roll-to-roll processing.
Co-reporter:Leijing Liu, Feipeng Chen, Bin Xu, Yujie Dong, Zujin Zhao, Wenjing Tian, Lu Ping
Synthetic Metals 2010 Volume 160(17–18) pp:1968-1972
Publication Date(Web):September 2010
DOI:10.1016/j.synthmet.2010.07.017
A pure-white organic light-emitting diode (WOLED) with a simple device architecture of indium tin oxide (ITO)/poly-(3,4-ethylenedioxythiophene):poly-(styrenesuphonic acid) (PEDOT:PSS)/L-Z-390/1,3,5-tri(N-phenylbenzimidazol-2-yl)benzene (TPBi)/LiF/Al was realized by using a single small molecule 3,3′-(2,7-Dis((9-(2,3,5,6-tetrafluorophenyl)-9H-carbazol-3-yl)ethynyl)-9H-fluorene-9,9-diyl)bis(9-heptyl-9H-carbazole) (L-Z-390) as the light-emitting material. The WOLED exhibited efficient white emission with a turn-on voltage of 6 V, a maximum luminous efficiency of 3.6 cd/A at 6 V, a maximum luminous of 204 cd/m2 at 13 V and Commission Internationale de l’Eclairage (CIE) coordinates of (0.33, 0.34). The device performance characteristics are among the best ever reported for solution-processed WOLEDs with a single-emitting small molecule. The white light comes from the combination of the blue emission originating from the excimer of L-Z-390 and the long-wavelength orange emission originating from the electromer of L-Z-390 under a high electric field. The double-layer device based on 3,3′-(2,7-Dis((9-(2,3,5,6-tetrafluorophenyl)-9H-carbazol-3-yl)ethynyl)-9H-fluorene-9,9-diyl)bis(9-(2,3,5,6-tetrafluorophenyl)-9H-carbazole) (L-Z-398), the other molecule with two more electron-withdrawing 2,3,5,6-tetrafluorophenyl units than L-Z-390, shows green EL under the high voltages. That L-Z-398 cannot form electromer under a high voltage may be because the L-Z-398 cannot stably form L-Z-398+ component and L-Z-398− component simultaneously due to the too strong electron-withdrawing ability of the four 2,3,5,6-tetrafluorophenyl units connected to each carbazole.
Co-reporter:Hongguang Lu, Bin Xu, Yujie Dong, Feipeng Chen, Yaowen Li, Zaifang Li, Jiating He, Hui Li and Wenjing Tian
Langmuir 2010 Volume 26(Issue 9) pp:6838-6844
Publication Date(Web):January 29, 2010
DOI:10.1021/la904727t
Three functionalized 9,10-distyrylanthracene (DSA) derivatives, namely, 9,10-bis(4-hydroxystyryl)anthracene (2), 9,10-bis{4-[2-(diethylamino)ethoxy]styryl}anthracene (4), and 9,10-bis{4-[2-(N,N,N-triethylammonium)ethoxy]styryl}anthracene dibromide (5), were synthesized and their fluorescence properties were investigated. The three DSA derivatives possess a typical aggregation-induced emission (AIE) property (i.e., they are nonluminescent in dilute solutions but are efficiently fluorescent as induced by molecular aggregation). Different AIE properties were tuned through molecular structure control. Dye 2 is a phenol-moiety-containing compound, which shows aggregation at pH values smaller than 10, resulting in a high fluorescence intensity. Thus, dye 2 has a pKa of 9.94. 4 is an amine-containing compound that starts to aggregate at slightly basic conditions, resulting in a pKa of 6.90. Dye 5 is an ammonium-salt-containing compound. Because it is very soluble in water, this compound has no AIE phenomenon but can interact strongly with protein or DNA to amplify its emission. Therefore, 5 is a fluorescent turn “on” biological probe for protein and DNA detection and it is also selective, which works for native BSA and ct DNA but not their denatured forms. Therefore, we not only developed a few new compounds showing the AIE phenomena but also controlled the AIE through environmental stimulation and demonstrated that the new AIE molecules are suitable for pH and biomacromolecule sensing.
Co-reporter:Yaowen Li;Zaifang Li;Chunyu Wang;Hui Li;Hongguang Lu;Bin Xu
Journal of Polymer Science Part A: Polymer Chemistry 2010 Volume 48( Issue 13) pp:2765-2776
Publication Date(Web):
DOI:10.1002/pola.24025
Abstract
A series of novel soluble donor-acceptor low-bandgap-conjugated polymers consisting of different oligothiophene (OTh) coupled to electron-accepting moiety 2-pyran-4-ylidenemalononitrile (PM)-based unit were synthesized by Stille or Suzuki coupling polymerization. The combination of electron-accepting PM building block with varied OThn (the number of thiophene unit increases from 3 to 5) results in enhanced π–π stacking in solid state and intramolecular charge transfer (ICT) transition, which lead to an extension of the absorption spectra of the copolymers. Cyclic voltammetry measurements and molecular orbital distribution calculations indicate that the highest occupied molecular orbitals (HOMO) energy levels could be fine-tuned by changing the number of thiophene units of the copolymers, and the resulting copolymers possessed relatively low HOMO energy levels promising good air stability and high-open circuit voltage (Voc) for photovoltaic application. Bulk heterojunction photovoltaic devices were fabricated by using the copolymers as donors and (6,6)-phenyl C61-butyric acid methyl ester as acceptor. It was found that the highest Voc reached 0.94 V, and the short circuit currents (Jsc) were improved from 1.78 to 2.54 mA/cm2, though the power conversion efficiencies of the devices were measured between 0.61 and 0.99% under simulated AM 1.5 solar irradiation of 100 mW/cm2, which indicated that this series copolymers can be promising candidates for the photovoltaic applications. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2765–2776, 2010
Co-reporter:Yaowen Li, Hui Li, Bin Xu, Zaifang Li, Feipeng Chen, Dongqing Feng, Jibo Zhang, Wenjing Tian
Polymer 2010 Volume 51(Issue 8) pp:1786-1795
Publication Date(Web):6 April 2010
DOI:10.1016/j.polymer.2010.01.039
A series of novel soluble conjugated copolymers consisting of electron-accepting 2-pyran-4-ylidenemalononitrile (PM) and electron-donating fluorene connected by different electron-donating ability conjugated moieties were synthesized by Suzuki coupling polymerization. The structures of the copolymers were characterized and their physical properties were investigated. High molecular weight (Mn up to 43.8 kg/mol) and thermostable copolymers were obtained. The conjugated bridge between PM and fluorene building block with gradually increased electron-donating ability moieties results in enhanced intramolecular charge transfer (ICT) transition bands, which lead to an extension of their absorption spectral range. Cyclic voltammetry measurement displayed that the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the copolymers can be fine-tuned. The resulting copolymers possessed relatively low HOMO energy levels, promising good air stability and high open circuit voltage (Voc) for photovoltaic application. Bulk heterojunction photovoltaic devices were fabricated by using the copolymers as donors and (6,6)-phenyl C61-butyric acid methyl ester (PCBM) as acceptor. The power conversion efficiencies (PCE) of the devices were in the range of 0.02–0.52% under simulated AM 1.5 solar irradiation of 100 mW/cm2, and the highest Voc reached 0.82 V. The significant improvement of PCE indicates a novel concept for developing donor–acceptor (D–A) conjugated copolymers with high photovoltaic performance by adjusting electron-donating ability of conjugated bridge.
Co-reporter:Zaifang Li ; Jianing Pei ; Yaowen Li ; Bin Xu ; Meng Deng ; Zhaoyang Liu ; Hui Li ; Hongguang Lu ; Qiang Li
The Journal of Physical Chemistry C 2010 Volume 114(Issue 42) pp:18270-18278
Publication Date(Web):October 5, 2010
DOI:10.1021/jp1042848
A series of solution processable small molecules (4TPM, 6TPM, and 8TPM) were synthesized with 2-pyran-4-ylidenemalononitrile (PM) as the electron-accepting unit and oligothiophene with different numbers as the electron-donating unit. Differential scanning calorimetry (DSC) measurement indicated that melting point and crystal temperature of molecules increased with the increase of thiophene number. UV−vis absorption demonstrated that the combination of PM with oligothiophene resulted in an enhanced intramolecular charge transfer (ICT) transition, which led to an extension of the absorption of the molecules. Cyclic voltammetry investigation displayed that the highest occupied molecular orbital (HOMO) energy levels of the three molecules were relatively low, which promised good air stability and high open circuit voltage (Voc) for photovoltaic application. Theoretical calculations revealed that the variation laws of HOMO and the lowest unoccupied molecular orbital (LUMO) energy levels are well consistent with cyclic voltammetry measurement. The bulk heterojunction (BHJ) photovoltaic devices with the structure of ITO/PEDOT−PSS/small molecules−PCBM/LiF/Al were fabricated, with the three molecules as donor and (6,6)-phenyl-C61-butyric acid methyl ester (PCBM) as the acceptor. The device based on 6TPM/PCBM (30:70 w/w) successfully achieved a maximum power conversion efficiency (PCE) of 1.15% under the illumination of AM 1.5, 100 mW/cm2.
Co-reporter:Bin Xu, Honghua Fang, Feipeng Chen, Hongguang Lu, Jiating He, Yaowen Li, Qidai Chen, Hongbo Sun and Wenjing Tian
New Journal of Chemistry 2009 vol. 33(Issue 12) pp:2457-2464
Publication Date(Web):06 Oct 2009
DOI:10.1039/B9NJ00393B
Three π-conjugated dendrimers (Ph-G0, Ph-G1 and Ph-G2) bearing triphenylamine moieties have been synthesized through a convergent synthetic strategy without any protection–deprotection chemistry. The linear photophysical properties, two-photon absorption (TPA), and optical limiting behavior of the dendrimers were investigated in solution at room temperature. Linear absorption and emission spectra revealed a bathochromic shift and decreased fluorescence quantum yields with increasing dendrimer generation. A strong cooperative effect in the TPA absorption of these dendrimers was observed. The TPA cross-sections increase gradually with the proportion of triphenylamine units and the maximum value of the TPA cross-section can reach 5690 GM for Ph-G2. These triphenylamine-based dendrimers exhibited efficient two-photon optical limiting under femtosecond excitation.
Co-reporter:Kunpeng Li, Jiali Qu, Bin Xu, Yinhua Zhou, Leijing Liu, Ping Peng and Wenjing Tian
New Journal of Chemistry 2009 vol. 33(Issue 10) pp:2120-2127
Publication Date(Web):10 Aug 2009
DOI:10.1039/B9NJ00236G
Three conjugated dendrimers containing electron-accepting sulfonyldibenzene (SDB) cores and electron-donating triphenylamine dendrons have been synthesized through a convergent synthetic strategy without any protection/deprotection chemistry. The dendrimers were highly soluble in common organic solvents, and could form good quality optical films by spin coating. Their thermal, optical and electrical properties are manipulated by attaching different peripheral dendrons. Using these dendrimers as donors and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) as acceptor, the bulk heterojunction solar cells with a structure of ITO–PEDOT–dendrimers:PCBM–LiF–Al were fabricated. The cell based on dendrimer G0 shows a relatively high power-conversion efficiency (PCE) of 0.34% under AM 1.5 illumination of 100 mW cm−2.
Co-reporter:Zhongfeng Yang, Bin Xu, Jiating He, Lili Xue, Qing Guo, Haijian Xia, Wenjing Tian
Organic Electronics 2009 Volume 10(Issue 5) pp:954-959
Publication Date(Web):August 2009
DOI:10.1016/j.orgel.2009.04.024
Two solution processable π-conjugated triphenylamine-based dendrimers, Tr-TPA3 and Tr-TPA9 were served as hole-transporting materials (HTMs) for organic light-emitting devices (OLEDs). The two dendrimers exhibit similar absorption and emission behaviors in solutions and thin films, which demonstrate that these dendrimers can form amorphous states in their films. The dendrimers showed excellent solubility, which are soluble in common organic solvents such as chloroform, tetrahydrofuran, and 1,1,2,2-tetrachloroethane, high thermal stability with high glass-transition temperature (Tg) of 115 °C for Tr-TPA3 and 140 °C for Tr-TPA9, high the highest unoccupied molecular orbital (HOMO) energy level (−5.12 eV for Tr-TPA3 and −4.95 eV for Tr-TPA9, respectively) and good film forming property. When we employed these dendrimers as hole transport layer (HTL) in tris-(8-hydroxyquinoline) aluminum (Alq3)-emitting electroluminescence (EL) devices, the Tr-TPA9-based double-layer device exhibited the turn-on voltage of 2.5 V, the maximum luminance of about 11,058 cd m−2 and the maximum current efficiency of 4.01 cd A−1. The comparison of the properties between the EL devices with dendrimers as HTL and the EL device with 1,4-bis(1-naphthylphenylamino)biphenyl (NPB) as HTL indicated that this series of dendrimers can be good candidates for HTM in OLEDs.
Co-reporter:John A. Mikroyannidis, Qingfeng Dong, Bin Xu, Wenjing Tian
Synthetic Metals 2009 Volume 159(15–16) pp:1546-1551
Publication Date(Web):August 2009
DOI:10.1016/j.synthmet.2009.04.014
A soluble alternating vinylene-copolymer P and the corresponding model compound M were synthesized by Heck coupling. They contained triphenylamine moieties and cyano-substituted olefinic bonds along the backbone. Both samples were stable up to about 300 °C and afforded char yields of 76–89% at 800 °C. Their glass transition temperature (Tg) was 72–78 °C and the absorption maximum was located at 307–366 nm with optical band gaps of 2.19–2.35 eV. They emitted yellow-orange light with photoluminescence (PL) maximum at 560–576 nm. Bulk heterojunction photovoltaic cells with the configuration of ITO/PEDOT:PSS/Sample:PCBM(1:1, w/w)/LiF/Al were fabricated. The PCE of devices based on P and M reached 0.09% and 0.07%, respectively.
Co-reporter:Shanpeng Wen;Jianing Pei;Yinhua Zhou;Lili Xue;Bin Xu;Yaowen Li
Journal of Polymer Science Part A: Polymer Chemistry 2009 Volume 47( Issue 4) pp:1003-1012
Publication Date(Web):
DOI:10.1002/pola.23158
Abstract
A novel poly(p-phenylenevinylene) PPV-based copolymer (3C-OXD-PPV) with electron-deficient oxadiazole segments as the side chain has been successfully synthesized through the Gilch polymerization. The obtained copolymer is soluble in common organic solvents such as chloroform, tetrahydronfuran, and 1,1,2,2-tetrachloroethane. The copolymer was characterized by 1H NMR, elemental analysis and GPC. TGA measurement of the copolymer shows it has good thermal stability with decomposition temperature higher than 350 °C. The absorption, electrochemical properties of the 3C-OXD-PPV were investigated and also compared with the properties of MEH-PPV. The HOMO and LUMO levels of 3C-OXD-PPV were estimated from the electrochemical cyclic voltammograms. Bulk-heterojunction PVCs were fabricated by using 3C-OXD-PPV blended PCBM as an active layer. The PCE of the PVC is 1.60% under 100 mW cm−2 AM 1.5 illumination, which indicates that 3C-OXD-PPV is a potential candidate for the application of polymer PVC. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1003–1012, 2009
Co-reporter:Lili Xue, Jiating He, Xin Gu, Zhongfeng Yang, Bin Xu and Wenjing Tian
The Journal of Physical Chemistry C 2009 Volume 113(Issue 29) pp:12911-12917
Publication Date(Web):June 25, 2009
DOI:10.1021/jp902976w
A symmetrical D-π-A-π-D organic dye molecule 2-{2,6-bis-[2-(4-diphenylamino-phenyl)-vinyl]-pyran-4-ylidene}-malononitrile (DADP) has been introduced into solution-processable organic solar cells (S-P OSCs). Detailed investigations on the relationship between its molecular structure and thermal, photophysical, electrochemical properties and electronic structure are described. The optimized bulk heterojunction solar cell based on DADP as donor and PCBM as acceptor with the configuration of ITO/PEDOT/DADP:PCBM/LiF/Al exhibits a Voc of 0.98 V, Isc of 4.16 mA/cm2, FF of 0.37, and power conversion efficiency (PCE) of 1.50% under the illumination of AM 1.5 simulated solar light (100 mW/cm2). It was noted that the PCE of the device based on DADP is almost double that of the device based on TPA-DCM-TPA, an analogue of DADP, although there is only a small difference between their molecular structures; DADP has a shorter distance between the triphenylamine (TPA) group and the 2-pyran-4-ylidenemalonitrile (PM) group than TPA-DCM-TPA. This small structural difference results in a lower-lying highest occupied molecular orbital (HOMO) energy level and higher hole mobility in DADP, and ultimately leads to the increased PCEs of the DADP-based devices.
Co-reporter:Jiating He, Bin Xu, Feipeng Chen, Haijian Xia, Kunpeng Li, Ling Ye and Wenjing Tian
The Journal of Physical Chemistry C 2009 Volume 113(Issue 22) pp:9892-9899
Publication Date(Web):May 8, 2009
DOI:10.1021/jp900205k
We have studied the crystal structures and photophysical properties of four 9,10-distyrylanthracene (DSA) derivatives. Their crystal structures exhibit nonplanar conformations due to the supramolecular interactions resulting in rigid molecules and relative tight stacking. The four DSA derivatives possess a typical aggregation-induced emission (AIE) property, i.e., they exhibit faint emission in their solutions but intense emission in their crystals as a result of the dominant nonradiative decay by free intramolecular torsion in the solution and the restricted torsional motion by supramolecular interaction in the crystal. The investigation of the relationship between the crystal structures and AIE properties of the four DSA derivatives indicates that DSA moiety is the key factor of AIE property because of the restricted intramolecular torsion between the 9,10-anthrylene core and the vinylene moiety.
Co-reporter:Yinhua Zhou, Jianing Pei, Qingfeng Dong, Xiaobo Sun, Yunqi Liu and Wenjing Tian
The Journal of Physical Chemistry C 2009 Volume 113(Issue 18) pp:7882-7886
Publication Date(Web):April 10, 2009
DOI:10.1021/jp811522p
We fabricated polymer-based bulk heterojunction (BHJ) solar cells using a donor−acceptor (D-A) molecule N-propyl-3,6-bis[2-(3-dicyanomethylene-5,5-dimethylcyclohex-1-enyl)vinyl]carbazole (PDHC) as the acceptor. The strong photoluminescence (PL) quenching of poly[2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) when mixed with PDHC means that efficient charge transfer has happened between MEH-PPV and PDHC. We used MEH-PPV and poly (3-hexylthiophene) (P3HT) as the donors and PDHC as the acceptor to fabricate BHJ solar cells. The cells with the structure of ITO/PEDOT/polymer:PDHC/LiF/Al exhibited a power conversion efficiency (PCE) about 0.2% under 100 mW/cm2 white light illumination. The open-circuit voltages (Vocs) of 1.14 V of the cells based on MEH-PPV:PDHC and about 0.76 V of the cells based on P3HT:PDHC were achieved, which are higher than the Vocs of the corresponding solar cells with phenyl-C-butyric acid methyl ester (PCBM) as the acceptor. In comparison with the cells based on PCBM, the relatively lower PCE of solar cells based on PDHC is due to its low electron mobility of 1.15 × 10−5 cm2 V−1 S−1 estimated by the space charge limited current method.
Co-reporter:Yaowen Li, Lili Xue, Hui Li, Zaifang Li, Bin Xu, Shanpeng Wen and Wenjing Tian
Macromolecules 2009 Volume 42(Issue 13) pp:4491-4499
Publication Date(Web):May 12, 2009
DOI:10.1021/ma900623p
A series of novel soluble conjugated copolymers consisting of coplanar donor (bithiophenevinyl)−acceptor (2-pyran-4-ylidenemalononitrile) (TVM)-based unit coupled to different electron-donating ability moieties were synthesized by Suzuki coupling polymerization. The structures of the copolymers were characterized, and their physical properties were investigated. High molecular weight (Mn up to 43.8 kg/mol) and thermostable copolymers were obtained. The combination of TVM unit building block with gradually increased electron-donating ability moieties results in enhanced π−π stacking in solid state and intramolecular charge transfer (ICT) transition bands, which lead to an extension of their absorption spectral range. Cyclic voltammetry measurement displayed that the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the copolymers can be fine-tuned. The resulting copolymers possessed relatively low HOMO energy levels promising good air stability and high open-circuit voltage (Voc) for photovoltaic application. Bulk heterojunction photovoltaic devices were fabricated by using the copolymers as donors and (6,6)-phenyl C61-butyric acid methyl ester (PCBM) as acceptor. It was found that the Voc reached 0.90 V, and the power conversion efficiencies (PCE) of the devices were measured between 0.04% and 0.99% under simulated AM 1.5 solar irradiation of 100 mW/cm2. The significant improvement of PCE indicates a novel concept for developing TVM-based donor−acceptor (D−A) conjugated copolymers with high photovoltaic performance by adjusting electron-donating ability and coplanarity.
Co-reporter:Shanpeng Wen, Jianing Pei, Yinhua Zhou, Pengfei Li, Lili Xue, Yaowen Li, Bin Xu and Wenjing Tian
Macromolecules 2009 Volume 42(Issue 14) pp:4977-4984
Publication Date(Web):July 2, 2009
DOI:10.1021/ma900598c
Three novel conjugated copolymers containing alkoxylated 4,7-diphenyl-2,1,3-benzothiadiazole and dialkylfluorene or dialkyloxyphenylene or dialkylthiophene units were prepared by Horner polycondensation reactions. They are all soluble in common organic solvents such as chloroform, tetrahydrofuran, and chlorobenzene. The novel copolymers were characterized by NMR, GPC, and elemental analysis. Thermogravimetric analysis of the copolymers showed they have good thermal stability with the decomposition temperature higher than 350 °C. Cyclic voltammetric study shows that the HOMO energy levels of the three copolymers are deep-lying which implies that these copolymers have good stability in the air and the relatively low HOMO energy level assures a higher open circuit potential when they are used in photovoltaic cells. Bulk-heterojunction photovoltaic cells were fabricated with the copolymers as the donors and PCBM as the acceptor. The cells based on the three copolymers exhibited power conversion efficiencies of 0.65, 1.25, 1.62% with high open circuit potential of 0.76, 0.96, and 1.04 V under one sun of AM 1.5 solar simulator illumination (100 mW/cm2).
Co-reporter:Lili Xue, Leijing Liu, Qiang Gao, Shanpeng Wen, Jiating He, Wenjing Tian
Solar Energy Materials and Solar Cells 2009 93(4) pp: 501-507
Publication Date(Web):
DOI:10.1016/j.solmat.2008.10.028
Co-reporter:Zujin Zhao, Bin Xu, Zhongfeng Yang, Hongyan Wang, Xiaoming Wang, Ping Lu and Wenjin Tian
The Journal of Physical Chemistry C 2008 Volume 112(Issue 23) pp:8511-8515
Publication Date(Web):May 16, 2008
DOI:10.1021/jp8028215
A series of highly fluorescent, fluorinated carbazole derivatives have been synthesized and fully characterized. “Pure” white light consisting of a blue light from excimers and an orange light from electromers at a high voltage has been achieved by using these compounds as single-emitting components in organic light-emitting diodes (OLEDs).
Co-reporter:Yaowen Li;Lili Xue;Haijian Xia;Bin Xu;Shanpeng Wen
Journal of Polymer Science Part A: Polymer Chemistry 2008 Volume 46( Issue 12) pp:3970-3984
Publication Date(Web):
DOI:10.1002/pola.22737
Abstract
A series of novel soluble polythiophene derivatives containing triphenylamine moiety were synthesized by Grignard metathesis (GRIM) method. The structures of the polymers were characterized and their physical properties were investigated. High molecular weight (Mn up to 25,800 g/mol) and thermostable polymers were obtained. The absorption spectra demonstrated that the absorption wavelength of the polymers could be tuned dramatically by introducing thiophene units in the main chain of the polymers. Photoluminescence spectra indicated that there was intramolecular energy transfer from the side chain to the main chain, and the maximum emission was red-shifted gradually with the increase of thiophene units in the main chain. Cyclic voltammetry displayed that the polymers possessed relatively high oxidation potential, which promised good air stability and high open circuit voltage for photovoltaic cells application. Finally, bulk heterojunction photovoltaic devices were fabricated by using the polymers as donors and (6,6)-phenyl C61-butyric acid methyl ester (PCBM) as acceptor. The maximal open circuit voltage of the photovoltaic cells reached 0.71–0.87 V and the power conversion efficiencies of the devices were measured between 0.014% and 0.45% under white light at 100 mW/cm2. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3970–3984, 2008
Co-reporter:
Analytical Methods (2009-Present) 2014 - vol. 6(Issue 7) pp:NaN2342-2342
Publication Date(Web):2014/01/08
DOI:10.1039/C3AY42255K
A fluorescent turn-on approach for the sensitive and selective sensing of Hg2+ based on an aggregation-induced emission fluorescent molecule (DSA-T2) containing 9,10-distyrylanthracene as a fluorophore and thymine as a Hg2+ receptor, was developed. Under optimum conditions, a linear relationship (R2 = 0.9894) was obtained between the fluorescent intensity and the concentration of Hg2+ from 7 × 10−7 mol L−1 to 1 × 10−5 mol L−1. The theoretical detection limit of Hg2+ was evaluated to be 3.4 × 10−7 mol L−1. And the selectivity towards Hg2+ was good compared to other metal ions.
Co-reporter:Jiaxing Song, Weidong Hu, Xiao-Feng Wang, Gang Chen, Wenjing Tian and Tsutomu Miyasaka
Journal of Materials Chemistry A 2016 - vol. 4(Issue 21) pp:NaN8443-8443
Publication Date(Web):2016/04/26
DOI:10.1039/C6TA01074A
Despite the potential of ZnO as the electron collection material for low-temperature processed perovskite solar cells (PSCs), previous investigations revealed that the CH3NH3PbI3-based perovskite rapidly decomposes on ZnO at elevated temperature through a deprotonation process (base-induced reaction) that reduces thermal stability. To solve this thermal instability issue and to further enhance the photovoltaic performance, we employed a (FA)-based perovskite, i.e., FAPbI3 as the light absorber in ZnO-based PSCs. The photovoltaic performance of the investigated FAPbI3 solar cells was clearly dependent on both the pre-heating of the PbI2 precursor and post-annealing of the FAPbI3 film in the solar cell fabrication procedure. The highest power conversion efficiency of up to 16.1% was achieved under AM 1.5 simulated sunlight illumination, in which the pre-heating and post-annealing temperatures were 100 °C and 145 °C, respectively. Importantly, the thermostability of the perovskite film on ZnO was substantially improved with FAPbI3 owing to basically the robust nature of FA compared with methylammonium (MA) in CH3NH3PbI3. Moreover, FAPbI3-based PSCs exhibited excellent photostability and small J–V hysteresis, which are all useful characteristics for further commercialization of low-temperature processed ZnO solar cells.
Co-reporter:Yujie Dong, Jibo Zhang, Xiao Tan, Lijuan Wang, Jinlong Chen, Bao Li, Ling Ye, Bin Xu, Bo Zou and Wenjing Tian
Journal of Materials Chemistry A 2013 - vol. 1(Issue 45) pp:NaN7559-7559
Publication Date(Web):2013/09/17
DOI:10.1039/C3TC31553C
A novel divinylanthracene derivative 9,10-bis((E)-2-(pyridin-4-yl)vinyl)anthracene (BP4VA) was synthesized and its two polymorphs with different crystal structures were obtained. The introduction of pyridine in BP4VA leads to multi-stimuli responsive fluorescence. An investigation of the photophysical and stimuli responsive luminescent properties of BP4VA, including the piezochromism and protonation effect, demonstrates that the piezochromic luminescence originates from changes in the molecular aggregation state. Additionally, protonation–deprotonation of the pyridine moieties in BP4VA has a significant effect on the frontier molecular orbitals, resulting in distinct green and red emissions under acid and base stimuli. This study on BP4VA provides a comprehensive insight into the mechanisms within this type of stimuli-responsive luminescent material, and suggests that BP4VA may be a potential candidate for applications in sensing, detection and display devices with remarkable color-changing properties.
Co-reporter:Lijuan Wang, Bin Xu, Jibo Zhang, Yujie Dong, Shanpeng Wen, Houyu Zhang and Wenjing Tian
Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 7) pp:NaN2458-2458
Publication Date(Web):2012/11/21
DOI:10.1039/C2CP41876B
The electronic structure and charge transport property of 9,10-distyrylanthracene (DSA) and its derivatives with high solid-state luminescent efficiency were investigated by using density functional theory (DFT). The impact of substituents on the optimized structure, reorganization energy, ionization potential (IP) and electronic affinity (EA), frontier orbitals, crystal packing, transfer integrals and charge mobility were explored based on Marcus theory. It was found that the hole mobility of DSA was 0.21 cm2 V−1 s−1 while the electron mobility was 0.026 cm2 V−1 s−1, which were relatively high due to the low reorganization energies and high transfer integrals. The calculated results showed that the charge transport property of these compounds can be significantly tuned via introducing different substituents to DSA. When one electron-withdrawing group (cyano group) was introduced into DSA, DSA–CN exhibited hole mobility of 0.14 cm2 V−1 s−1 which was on the same order of that of DSA. However, the electron mobility of DSA–CN decreased to 8.14 × 10−4 cm2 V−1 s−1 due to the relatively large reorganization energy and disadvantageous transfer integral. The effect of electron-donating substituents was investigated by introducing methoxy group and tertiary butyl into DSA. DSA–OCH3 and DSA–TBU showed much lower charge mobility than DSA resulting from the steric hindrance of substituents. On the other hand, both of them exhibited balanced transport properties (for DSA–OCH3, the hole and electron mobility was 0.0026 and 0.0027 cm2 V−1 s−1; for DSA–TBU, the hole and electron mobility was 0.045 and 0.012 cm2 V−1 s−1) because of their similar transfer integrals for both hole and electron. DSA and its derivatives were supposed to be one of the most excellent emissive materials for organic electroluminescent applications because of their high charge mobility and high solid-state luminescent efficiency.
Co-reporter:Yang Liu, Roderick. C. I. MacKenzie, Bin Xu, Yajun Gao, Miquel Gimeno-Fabra, David Grant, Paul. H. M. van Loosdrecht and Wenjing Tian
Journal of Materials Chemistry A 2015 - vol. 3(Issue 47) pp:NaN12266-12266
Publication Date(Web):2015/11/10
DOI:10.1039/C5TC02678D
Recently, Gao et al. reported being able to measure significant quantities of photogenerated charge up to one hour after it had been generated in an organic semiconductor device. The aim of this paper is twofold; (a) to provide conclusive experimental evidence to support the picture of device operation; and (b) to understand and demonstrate how changes to the device structure and materials can be used to tune the charge carrier lifetime. By tuning both the materials used, and the device structure we are able to observe a charge carrier life time of over 2 hours and still extract significant amounts of charge from the device after 5 hours. This is achieved by engineering the band structure of the device to control the spatial overlap of the stored photoexcited electron and hole populations and thus the recombination rate. By performing lifetime measurements as a function of charge carrier density and applied voltage we find the recombination rate has a 0th order dependence on carrier density, and elucidate the mechanisms responsible for these long charge carrier life times. This work is of technological significance for the development of organic electronic high sensitivity photodetectors and memory elements.
Co-reporter:Shiyu Yao, Pengfei Li, Ji Bian, Qingfeng Dong, Chan Im and Wenjing Tian
Journal of Materials Chemistry A 2013 - vol. 1(Issue 37) pp:NaN11450-11450
Publication Date(Web):2013/08/15
DOI:10.1039/C3TA11972F
A new quaternized ammonium polyfluorene polyelectrolyte poly[3,3′-(2-(3-hexyl-5-(7-(4-hexyl-5-methylthiophen-2-yl)benzo[c][1,2,5]thiadiazol-4-yl)thiophen-2-yl)-7-methyl-9H-fluorene-9,9-diyl)bis(N,N-dimethylpropan-1-amine)]dibromide (PFBTBr) is applied as the cathode interfacial layer of a polymer solar cell based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PC61BM). Electrostatic force microscopy (EFM) measurements of PFBTBr layers demonstrate the formation of the interfacial dipole between the active layer and the cathode by inserting a PFBTBr interfacial layer. Atomic force microscopy (AFM) measurements of PFBTBr layers with varied concentrations show that the morphology of the PFBTBr layer plays a direct, important role in the contact quality between the active layer and the PFBTBr interfacial layer, which can strongly affect the performance of devices. X-ray photoelectron spectroscopy measurements (XPS) indicate that PFBTBr may serve as a protective agent for the active layer against Al-induced degradation, since it prevents hot aluminum atoms from diffusing into the active layer. The power conversion efficiency (PCE) of the PSCs with the PFBTBr layer reaches 3.9% under the illumination of AM 1.5G, 100 mW cm−2, which is 1.6 times higher in comparison with that (2.4%) of the device without the PFBTBr layer. The significant increase in efficiency and easy utilization indicate that this interfacial material has promising and practical application prospects.
Co-reporter:Jiaxing Song, Enqiang Zheng, Ji Bian, Xiao-Feng Wang, Wenjing Tian, Yoshitaka Sanehira and Tsutomu Miyasaka
Journal of Materials Chemistry A 2015 - vol. 3(Issue 20) pp:NaN10844-10844
Publication Date(Web):2015/04/09
DOI:10.1039/C5TA01207D
We demonstrated SnO2 films prepared by sinter-less spin-coating processes as an electron selective contact for CH3NH3PbI3-based planar-heterojunction perovskite solar cells (PSCs). A modified sequential deposition method, in which the grain size of PbI2 precursors was controlled by an equivalent solvent vapor annealing (SVA) process, was used to prepare the perovskite layer on SnO2. With this SVA process, the remnant PbI2 nanocrystals can stably occur at the interface of CH3NH3PbI3/SnO2 to carry out a passivation effect. The photovoltaic performance of SnO2-based PSCs is dependent on both the SVA time and the thickness of the perovskite layer. The optimized PSC device achieves the best power conversion efficiency of up to 13% under the AM 1.5 simulated sunlight illumination, which is highly durable over 30 days of storage time with exposure to the ambient air environment.
Co-reporter:Bin Xu, Jiating He, Yujie Dong, Feipeng Chen, Weili Yu and Wenjing Tian
Chemical Communications 2011 - vol. 47(Issue 23) pp:NaN6604-6604
Publication Date(Web):2011/05/16
DOI:10.1039/C1CC11706H
Conjugated oligocarbazoles with a 9,10-divinylanthracene core have been synthesized, and exhibit the transition from aggregation-induced emission (AIE) to aggregation-induced emission enhancement (AIEE) behaviour with extending conjugation length; self-assembly of the Cz4 molecule affords nanorings with high fluorescent efficiency.
Co-reporter:
Analytical Methods (2009-Present) 2013 - vol. 5(Issue 2) pp:
Publication Date(Web):
DOI:10.1039/C2AY26202A
A label-free fluorescence turn-on approach for the selective sensing of Pb2+ based on quaternary ammonium salt of 9,10-distyrylanthracene with aggregation-induced emission (AIE) property was developed through Pb2+-induced allosteric G-quadruplex (G4). The method is simple, easy to operate, cost-effective, and provides good sensitivity and selectivity.
Co-reporter:Jibo Zhang, Suqian Ma, Honghua Fang, Bin Xu, Hongbo Sun, Im Chan and Wenjing Tian
Inorganic Chemistry Frontiers 2017 - vol. 1(Issue 7) pp:NaN1429-1429
Publication Date(Web):2017/03/01
DOI:10.1039/C7QM00032D
9,10-Distyrylanthracene (DSA) and its four derivatives are investigated by both steady state and ultrafast spectroscopy to reveal the intrinsic photophysical process upon excitation. Intramolecular rotation around the vinyl moiety plays an important role in the whole photophysical process in addition to the electronic properties of the peripheral substituents. In dilute solutions, DSA derivatives possess a twisted structure in the ground state that eventually relaxes to a planar structure within picoseconds. The fluorescence process is dominated by the relaxed excited state, and the quantum yield is affected by competition between the nonradiative and radiative deactivations. The enhanced fluorescence of the molecular aggregates originates from the optically allowed S1–S0 transition together with the suppressed nonradiative deactivation via molecular stacking. These findings provide an in-depth understanding of the origin of the aggregation enhanced emission process, and may be applicable for the fine design of DSA based molecules with enhanced fluorescence and novel structures beyond DSA.
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![Spiro[2H-1-benzopyran-2,2'-[2H]indole], 1',3'-dihydro-1',3',3'-trimethyl-6-[2-[4-(1,2,2-triphenylethenyl)phenyl]ethenyl]-](/data/chemimg/3784100/1670271-25-6.png)
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![Spiro[2H-1-benzopyran-2,2'-[2H]indole]-1'(3'H)-propanoic acid, 3',3'-dimethyl-6-nitro-, 4-[1,2-bis[4-[3-(1',3'-dihydro-3',3'-dimethyl-6-nitrospiro[2H-1-benzopyran-2,2'-[2H]indol]-1'-yl)-1-oxopropoxy]phenyl]-2-phenylethenyl]phenyl ester](/data/chemimg/3784100/1952272-86-4.png)
![Spiro[2H-1-benzopyran-2,2'-[2H]indole]-1'(3'H)-propanoic acid, 3',3'-dimethyl-6-nitro-, 4-[1,2-bis[4-[3-(1',3'-dihydro-3',3'-dimethyl-6-nitrospiro[2H-1-benzopyran-2,2'-[2H]indol]-1'-yl)-1-oxopropoxy]phenyl]-2-phenylethenyl]phenyl ester](/data/chemimg/3784100/1952272-86-4_b.png)
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![2-Butenedinitrile, 2,3-bis[4-[2-[4-(diphenylamino)phenyl]ethenyl]phenyl]-](/data/chemimg/3784100/2047350-93-4.png)
![2-Butenedinitrile, 2,3-bis[4-[2-[4-(diphenylamino)phenyl]ethenyl]phenyl]-](/data/chemimg/3784100/2047350-93-4_b.png)
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![2-Butenedinitrile, 2-[4-[2-[4-(diethylamino)phenyl]ethenyl]phenyl]-3-phenyl-](/data/chemimg/3784100/2047350-99-0_b.png)
![2-Butenedinitrile, 2-[4-[2-[4-(dipropylamino)phenyl]ethenyl]phenyl]-3-phenyl-](/data/chemimg/3784100/2047351-02-8.png)
![2-Butenedinitrile, 2-[4-[2-[4-(dipropylamino)phenyl]ethenyl]phenyl]-3-phenyl-](/data/chemimg/3784100/2047351-02-8_b.png)
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![2-Butenedinitrile, 2-phenyl-3-[4-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]phenyl]-](/data/chemimg/3784100/2047351-05-1_b.png)
![2-Butenedinitrile, 2-[4-[2-[4-(9H-carbazol-9-yl)phenyl]ethenyl]phenyl]-3-phenyl-](/data/chemimg/3784100/2047351-08-4.png)
![2-Butenedinitrile, 2-[4-[2-[4-(9H-carbazol-9-yl)phenyl]ethenyl]phenyl]-3-phenyl-](/data/chemimg/3784100/2047351-08-4_b.png)
![2-Butenedinitrile, 2-phenyl-3-[4-[2-(4-[9,3':6',9''-ter-9H-carbazol]-9'-ylphenyl)ethenyl]phenyl]-](/data/chemimg/3784100/2047351-11-9.png)
![2-Butenedinitrile, 2-phenyl-3-[4-[2-(4-[9,3':6',9''-ter-9H-carbazol]-9'-ylphenyl)ethenyl]phenyl]-](/data/chemimg/3784100/2047351-11-9_b.png)
![2-Butenedinitrile, 2-[4-[2-[4-[bis[4-[2-[4-(diphenylamino)phenyl]ethenyl]phenyl]amino]phenyl]ethenyl]phenyl]-3-phenyl-](/data/chemimg/3784100/2047351-14-2.png)
![2-Butenedinitrile, 2-[4-[2-[4-[bis[4-[2-[4-(diphenylamino)phenyl]ethenyl]phenyl]amino]phenyl]ethenyl]phenyl]-3-phenyl-](/data/chemimg/3784100/2047351-14-2_b.png)
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![Benzaldehyde, 4,4'-[2,2-bis[4-(dimethylamino)phenyl]ethenylidene]bis-](/data/chemimg/3784100/2100282-97-9.png)
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![zinc (3S,4S,21R)-9-ethenyl-14-ethyl-21-(methoxycarbonyl)-4,8,13,18-tetramethyl-20-oxo-3-(3-oxo-3-{[(2E,7R,11R)-3,7,11,15-tetramethylhexadec-2-en-1-yl]oxy}propyl)-23,25-didehydrophorbine-23,25-diide](http://img.cochemist.com/ccimg/15800/15739-11-4.png)
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