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| 1 | Achieving over 16% efficiency for single-junction organic solar cells显示文摘To achieve high photovoltaic performance of bulk hetero-junction organic solar cells(OSCs), a range of critical factors including absorption profiles, energy level alignment, charge carrier mobility and miscibility of donor and acceptor materials should be carefully considered. For electron-donating materials, the deep highest occupied molecular orbital(HOMO) energy level that is beneficial for high open-circuit voltage is much appreciated. However, a new issue in charge transfer emerges when matching such a donor with an acceptor that has a shallower HOMO energy level. More to this point, the chemical strategies used to enhance the absorption coefficient of acceptors may lead to increased molecular crystallinity, and thus result in less controllable phase-separation of photoactive layer. Therefore, to realize balanced photovoltaic parameters, the donor-acceptor combinations should simultaneously address the absorption spectra, energy levels, and film morphologies. Here, we selected two non-fullerene acceptors, namely BTPT-4F and BTPTT-4F, to match with a wide-bandgap polymer donor P2F-EHp consisting of an imidefunctionalized benzotriazole moiety, as these materials presented complementary absorption and well-matched energy levels. By delicately optimizing the blend film morphology, we demonstrated an unprecedented power conversion efficiency of over 16% for the device based on P2F-EHp:BTPTT-4F, suggesting the great promise of materials matching toward high-performance OSCs. | Baobing Fan Difei Zhang Meijing Li Wenkai Zhong Zhaomiyi Zeng Lei Ying Fei Huang Yong Cao | 2019 | Science China Chemistry2019，62，6： | 38 |
| 2 | Breaking 12% efficiency in flexible organic solar cells by using a composite electrode显示文摘The performance of flexible organic solar cells(OSCs)significantly relies on the quality of transparent flexible electrode.Here,we used silver nanowires(AgNWs)with various weight ratios to dope high-conductive poly(3,4-ethylenedioxythiophene):polystyrene sulfonate(PH1000)to optimize the optical and electronic properties of PH1000 film.A high-quality flexible composite electrode PET/Ag-mesh/PH1000:AgNWs-20 with smooth surface,a low sheet resistance of 6Ω/sq and a high transmittance of 86%at 550-nm wavelength was obtained by doping 20 wt%AgNWs to PH1000(PH1000:AgNWs-20).The flexible OSCs based on the PET/Ag-mesh/PH1000:AgNWs-20 electrode delivered a power conversion efficiency(PCE)of12.07%with an open circuit voltage(Voc)of 0.826 V,a short-circuit current density(Jsc)of 20.90 m A/cm2and a fill factor(FF)of69.87%,which is the highest reported PCE for the flexible indium-tin oxide(ITO)-free OSCs.This work demonstrated that the flexible composite electrodes of PET/Ag-mesh/PH1000:AgNWs are promising alternatives for the conventional PET/ITO electrode,and open a new avenue for developing high-performance flexible transparent electrode for optoelectronic devices. | Guang Zeng Jingwen Zhang Xiaobin Chen Hongwei Gu Yaowen Li Yongfang Li | 2019 | Science China Chemistry2019，62，7： | 9 |
| 3 | Optimal bulk-heterojunction morphology enabled by fibril network strategy for high-performance organic solar cells显示文摘A bicontinuous network formed spontaneously upon film preparation is highly desirable for bulk-heterojunction(BHJ) organic solar cells(OSCs). Many donor-acceptor(D-A) type conjugated polymers can self-assemble into polymer fibrils in the solid state and such fibril-assembly can construct the morphological framework by forming a network structure, inducing the formation of ideal BHJ morphology. Our recent works have revealed that the fibril network strategy(FNS) can control the blend morphology in fullerene, non-fullerene and ternary OSCs. It has been shown that the formation of fibril network can optimize phase separation scale and ensure efficient exciton dissociation and charge carriers transport, thus leading to impressive power conversion efficiencies(PCEs) and high fill factor(FF) values. We believe that FNS will provide a promising approach for the optimization of active layer morphology and the improvement of photovoltaic performance, and further promote the commercialization of OSCs. | Tian Xia Yunhao Cai Huiting Fu Yanming Sun | 2019 | Science China Chemistry2019，62，6： | 4 |
| 4 | Recent progress of thin-film photovoltaics for indoor application显示文摘Indoor photovoltaics have attracted increasing attentions owing to their great potential in supplying energy for low power devices under indoor light in our daily life.The third generation thin-film solar cells,including dye-sensitized solar cells,perovskite solar cells and organic solar cells,have made rapid progress from the aspect of materials design to photovoltaic performance.This review provides an overview on the recent advances in the development of indoor photovoltaic technologies based on the third generation solar cells.The design principles of advanced thin-film indoor photovoltaics were also summarized according to the characteristics of indoor light and the advantages of the third generation solar cells.Finally,after summarizing the current research progress,the perspective on this topic is provided. | Nanfu Yan Chaowei Zhao Shengyong You Yuefeng Zhang Weiwei Li | 2020 | Chinese Chemical Letters2020，31，3： | 4 |
| 5 | Optimization of Ethylene Glycol Doped PEDOT:PSS Transparent Electrodes for Flexible Organic Solar Cells by Drop-coating Method显示文摘Fabrication of flexible transparent electrodes(FTEs) is one of the core technologies in the field of flexible electronics. Among multiple choices of FTEs, poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonic acid)(PEDOT:PSS) has shown its promising application in roll-to-roll manufacturing. A simple yet effective method for substantially boosting the conductivity of these conducting polymer films without causing large-domain aggregations is by adding ethylene glycol(EG) as dopant. Herein, we investigated in detail the effects of the secondary solvent of ethylene glycol(EG) on the optical and electrical characteristics of PEDOT:PSS films. The modified PEDOT:PSS FTEs were deposited using drop-coating techniques as it had greater compatibility for large-area samples than the conventional spin-coating method did. The 6% EG-doped PEDOT:PSS FTE via drop-coating method achieved a high figure of merit(FoM) value of 47.24 and the devices fabricated using the optimal PEDOT:PSS FTE yielded a high power conversion efficiency(PCE) of 8.89%, mostly attributed to the modified PEDOT:PSS films that had excellent optical and electrical characteristics with low surface roughness. These results suggested that EG-doping could effectively boost the conductivity of PEDOT:PSS films and that the modified PEDOT:PSS FTE is suitable for roll-to-roll manufacturing in the future. | Hui-Qin Cui Rui-Xiang Peng Wei Song Jian-Feng Zhang Jia-Ming Huang Li-Qiang Zhu Zi-Yi Ge | 2019 | Chinese Journal of Polymer Science2019，37，8： | 4 |
| 6 | Fluorination-substitution effect on all-small-molecule organic solar cells显示文摘Due to the strong crystallinity and anisotropy of small molecules, matched molecular photoelectric properties and morphologies between small molecules and non-fullerene acceptors are especially important in all-small-molecule organic solar cells(OSCs).Introducing fluorine atoms has been proved as an effective strategy to achieve a high device performance through tuning molecular energy levels, absorption and assembly properties. Herein, we designed a novel benzodithiophene-based small molecule donor BDTF-CA with deep highest occupied molecular orbital(HOMO) energy level. All-small-molecule OSCs were fabricated by combing non-fullerene acceptor IDIC with different fluorine-atom numbers. Two or four fluorine atoms were introduced to the end-capped acceptor of IDIC, which are named as IDIC-2 F and IDIC-4 F, respectively. With the increase of fluorination from IDIC to IDIC-4 F, the open circuit voltage(Voc) of the devices decreased, while hole and electron mobilities of the active layers increased by one order of magnitude. Contributed to the most balanced Voc, short-circuit current(Jsc) and fill factor(FF), the device based on BDTF-CA/IDIC-2 F achieved the highest power conversion efficiency of 9.11%. | Qiong Wu Dan Deng Jianqi Zhang Wenjun Zou Yang Yang Zhen Wang Huan Li Ruimin Zhou Kun Lu Zhixiang Wei | 2019 | Science China Chemistry2019，62，7： | 3 |
| 7 | The impact of fluorination on both donor polymer and non-fullerene acceptor:The more fluorine,the merrier显示文摘Fluorination of the donor polymer or non-fullerene acceptor (NFA) in an organic photovoltaic device is an effective method to improve device efficiency.Although there have been many studies on donor polymer fluorination,blends containing both a fluorinated donor and fluorinated NFA have rarely been reported.In this study,we use two donor polymers (4'-FT-HTAZ and 4'-FT-FTAZ) and two NFAs (ITIC-Th and ITIC-Th1) with different amounts of fluorine (from 2F to 6F) to investigate how the degree of fluorination in a blend impacts device performance.We find that fluorinating the NFA leads to a higher short-circuit current density (Jsc) and fill factor (FF),however,the open-circuit voltage (Voc) is decreased due to a depressed lowest unoccupied molecular orbital (LUMO) level.Adding additional fluorine to the donor polymer does not have a large effect on the Jsc or FF,but it does lead to an improved Voc.By fluorinating the NFA and having more fluorine on the donor polymer,we obtain both a high Jsc and Voc simultaneously,leading to a power conversion efficiency over 10% in the case of 4'-FT-FTAZ:ITIC-Th1,which has the most amount of fluorine (6F). | Nicole Bauer Qianqian Zhang Jeromy James Rech Shuixing Dai Zhengxing Peng Harald Ade Jiayu Wang Xiaowei Zhan Wei You | 2019 | Nano Research2019，12，9： | 3 |
| 8 | Black phosphorus nanoflakes as morphology modifier for efficient fullerene-free organic solar cells with high fill-factor and better morphological stability显示文摘Morphology of the donor:acceptor blend plays a critical role in the photovoltaic performance of the organic solar cells (OSCs).Herein,liquid-phase-exfoliated black phosphorus nanoflakes (BPNFs),for their outstanding electronic property and good compatibility to solution process,were applied to fullerene-free OSCs as morphology modifier.Revealed by X-ray scattering measurements,the PTB7-Th:IEICO-4F blends incorporated with BPNFs exhibit more ordered π-π stacking and promoted domain purity,contributing to lower charge transport resistance and suppressed charge recombination within the bulk heterojunction (BHJ).As a result,a high fill factor (FF) of 0.73 and a best power conversion efficiency (PCE) of 12.2% were obtained for fullerene-free OSCs based on PTB7-Th:IEICO-4F blends incorporating with BPNFs,which is among the highest FF of the as-cast fullerene-free OSCs with PCE over 12%.More importantly,the embedded BPNFs help to improve the morphological stability of the devices probably by retarding the phase mixing in the BHJ during the aging period.Besides,analogous enhancements were observed in another fullerene-free OSCs based on PBDB-T:ITIC.In a word,this work provides a new strategy of using two-dimentional nanoflakes as facile and universal morphology modifier for efficient fullerene-free OSCs. | Weitao Yang Long Ye Fenfa Yao Chuanhong Jin Harald Ade Hongzheng Chen | 2019 | Nano Research2019，12，4： | 3 |
| 9 | Flexible ITO-free organic solar cells over 10% by employing drop-coated conductive PEDOT:PSS transparent anodes显示文摘Highly conductive poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonic acid)(PEDOT:PSS) has been explored to fabricate flexible and stretchable conductors. Generally, PEDOT:PSS transparent anodes are prepared by spin-coating method. In this article, we adopt a method by dropping PEDOT:PSS aqueous solution on the PET plastic substrate to fabricate flexible electrodes. Compared with spin coating, drop-coating is simple and cost-effective with large-area fabrications. Through this method, we fabricated highly transparent conductive electrodes and systematically studied their electrical, optical, morphological and mechanical properties. With dimethyl sulfoxide/methanesulfonic acid(DMSO/MSA) treated PEDOT:PSS electrode,bendable devices based on non-fullerene system displayed an open-circuit voltage of 0.925 V, a fill factor of 70.74%, and a high power conversion efficiency(PCE) of 10.23% under 100 mW cm^(-2) illumination, which retained over 80% of the initial PCE value after 1000 bending cycles. Based on the findings, drop-coated PEDOT:PSS electrodes exhibited high suitability for the development of large-area and high-efficiency printed solar cell modules in the future. | Huiqin Cui Wei Song Billy Fanady Ruixiang Peng Jianfeng Zhang Jiaming Huang Ziyi Ge | 2019 | Science China Chemistry2019，62，4： | 3 |
| 10 | Additive-free non-fullerene organic solar cells with random copolymers as donors over 9% power conversion efficiency显示文摘In this study, a series of random conjugated polymers (PBDB-TBTn) as donors were designed and synthesized. In these polymers, benzodithiophene unit with thiophene conjugated side chains (BDT) are donor part, and two different content of benzo[1,2-c:4,5-c']dithiophene-4,8-dione (BDD) and difluorobenzothiadizole (BT) linked alkylthiophene are acceptor unit. Polymer solar cells (PSCs) were fabricated with ITIC as an acceptor, and over the power conversion efficiency (PCE) of 9%was obtained, with open circuit voltage (Voc) of 0.86 V, short-circuit current density (Jsc) of 16.84 mA/cm^2, and fill factor (FF) of 62.5%. These random conjugated polymers based solar cells are insensitive to solvent additives and thermal annealing. The performance of the device decreases gradually with the increasing of the proportion of fluorinated acceptor unit. The declining efficiency is due to the excessive fluorinated acceptor unit, which leads to over aggregated topography, destroys the effective charge transport pathways, and affects phase separation domain size between the donor and the acceptor. The phenomena are explained by the charge carrier recombination, atomic force microscope (AFM), and transmission electron microscope (TEM). These results indicate that proper addition of fluorinated acceptor units to build random copolymers can enhance the efficiency of organic photovoltaics toward additive-free and thermal annealing-free PSCs. | Meimei Wu Laitao Shi Yu Hu Lie Chen Ting Hu Youdi Zhang Zhongyi Yuan Yiwang Chen | 2019 | Chinese Chemical Letters2019，30，6： | 3 |
| 11 | A-π-D-π-A small-molecule donors with different end alkyl chains obtain different morphologies in organic solar cells显示文摘For bulk-heterojunction organic solar cells, the morphology of the blend films highly influence the exciton dissociation and charge transport process. In this work, two novel A-π-D-π-A(A represents the acceptor unit and D represents the donor unit) backbone structure small molecular electron donors based on two dimensional conjugated naphtho[1,2-b:5,6-b']dithiophene(NDT) with different end alkyl chains, named as NDT-3T-EH and NDT-3T-O, have been designed and synthesized. The photovoltaic property of NDT-3T-O-based device is better than that of the NDT-3T-EH and the best efficiency reaches 7.06%, and the photovoltaic property of NDT-3T-EH reaches 6.11%. The difference in the performance should be attributed to the different morphology and phase separation resulted from the different crystallinity and aggregation ability of two donors. The results demonstrate that the optimized end alkyl chains can be used to design A-π-D-π-A backbone structure small molecular electron donors for smallmolecule organic solar cells. | Yanan Shi Chen Yang Huan Li Lixuan Liu Ruimin Zhou Wenjun Zou Zhen Wang Qiong Wu Dan Deng Jianqi Zhang Kun Lu Zhixiang Wei | 2019 | Chinese Chemical Letters2019，30，4： | 3 |
| 12 | Materials and structures for the electron transport layer of efficient and stable perovskite solar cells显示文摘The electron transport layer plays a vital function in extracting and transporting photogenerated electrons, modifying the interface, aligning the interfacial energy level and minimizing the charge recombination in perovskite solar cells. This review summarizes the recent research progress on electron transport materials of metal oxides, organic molecules and multilayers. The doped metal oxides as electron transport materials in regular perovskite solar cells show improved device performance relative to their non-doped counterpart due to enhanced electron mobility and energy level alignment. The non-fullerene organic electron transport materials with better electron mobility and tunable energy level alignment need to be further designed and developed despite their advantages of mechanical flexibility and wide range tunability. The multilayer electron transport materials are suggested to be an important direction of research for efficient and stable perovskite solar cells because of their favorable synergistic interaction. | Shizhao Zheng Gaopeng Wang Tongfa Liu Lingyun Lou Shuang Xiao Shihe Yang | 2019 | Science China Chemistry2019，62，7： | 3 |
| 13 | Non-fullerene Acceptors with a Thieno[3,4-c]pyrrole-4,6-dione(TPD) Core for Efficient Organic Solar Cells显示文摘To achieve the red-shifted absorptions and appropriate energy levels of A-D-A type non-fullerene acceptors(NFAs), in this work, we design and synthesize two new NFAs, named TPDCIC and TPDCNC, whose electron-donating(D) unit is constructed by a thieno[3,4-c]pyrrole-4,6-dione(TPD) core attached to two cyclopentadithiophene(CPDT) moieties at both sides, and the electronaccepting(A) end-groups are 2-(3-oxo-2,3-dihydroinden-1-ylidene)malononitrile(IC) and 2-(3-oxo-2,3-dihydro-1 H-cyclopenta[b]naphthalen-1-ylidene)malononitrile(NC), respectively. Benefiting from TPD core, which easily forms quinoid structure and O···H or O···S intramolecular noncovalent interactions, TPDCIC and TPDCNC show more delocalization of π-electrons and perfect planar molecular geometries, giving the absorption ranges extended to 822 and 852 nm, respectively. Furthermore, the highest occupied molecular orbital(HOMO) levels of TPDCIC and TPDCNC remain relatively low-lying due to the electronegativity of the carbonyl groups on TPD core. Considering that the absorptions and energy levels of the two NFAs match well with those of a widely used polymer donor, PBDB-T, we fabricate two kinds of organic solar cells(OSCs) based on the PBDB-T:TPDCIC and PBDB-T:TPDCNC blended films, respectively. Through a series of optimizations, the TPDCIC-based devices yield an impressing power conversion efficiency(PCE)of 10.12% with a large short-circuit current density(JSC) of 18.16 mA·cm-2, and the TPDCNC-based ones exhibit a comparable PCE of9.80% with a JSC of 17.40 mA·cm-2. Our work is the first report of the TPD-core-based A-D-A type NFAs, providing a good reference for the molecular design of high-performance NFAs. | Shi-Zhe Geng Wei-Tao Yang Jian Gao Shui-Xing Li Min-Min Shi Tsz-Ki Lau Xin-Hui Lu Chang-Zhi Li Hong-Zheng Chen | 2019 | Chinese Journal of Polymer Science2019，37，10： | 3 |
| 14 | Simple non-fullerene electron acceptors with unfused core for organic solar cells显示文摘Two simple electron acceptors based on unfused bithiophene core and 1,1-dicyanomethylene-3-indanone end group were easily prepared via three synthetic steps. These acceptors exhibited broad absorption in the range of 300 nm to 800 nm, aligned energy levels and high crystallinity. When combined with a wide band gap donor polymer in non-fullerene solar cells, an initial power conversion efficiency of 2.4% was achieved. The relatively low efficiencies were due to the large phase separation in blended thin films, which is originated from their high aggregation tendency in thin films. Our results suggest that these electron acceptors with unfused core are promising candidates for commercial application of solar cells due to the low cost starting materials and facile synthesis. | Yao Li Yunhua Xu Fan Yang Xudong Jiang Cheng Li Shengyong You Weiwei Li | 2019 | Chinese Chemical Letters2019，30，1： | 2 |
| 15 | Regulating the morphology of fluorinated non-fullerene acceptor and polymer donor via binary solvent mixture for high efficiency polymer solar cells显示文摘Fluorinated non-fullerene acceptors(NFAs) usually have planar backbone and a higher tendency to crystallize compared to their non-fluorinated counterparts, which leads to enhanced charge mobility in organic solar cells(OSCs). However, this selforganization behavior may result in excessive phase separation with electron donors and thereby deteriorate device efficiency.Herein, we demonstrate an effective approach to tune the molecular organization of a fluorinated NFA(INPIC-4 F), and its phase separation with the donor PBDB-T, by varying the casting solvent. A prolonged film drying time encourages the crystallization of INPIC-4 F into spherulites and consequently results in excessive phase separation, leading to a low device power conversion efficiency(PCE) of 8.1%. Contrarily, a drying time leads to fine mixed domains with inefficient charge transport properties,resulting in a moderate device PCE of 11.4%. An intermediate film drying time results in the formation of face-on π-π stacked PBDB-T and INPIC-4 F domains with continuous phase-separated networks, which facilitates light absorption, exciton dissociation as well as balanced charge transport towards the electrode, and achieves a remarkable PCE of 13.1%. This work provides a rational guide for optimizing the molecular ordering of NFAs and electron donors for high device efficiency. | Mengxue Chen Zhuohan Zhang Wei Li Jinlong Cai Jiangsheng Yu Emma L. K. Spooner Rachel C. Kilbride Donghui Li Baocai Du Robert S. Gurney Dan Liu Weihua Tang David G. Lidzey Tao Wang | 2019 | Science China Chemistry2019，62，9： | 2 |
| 16 | 超柔性薄膜有机半导体器件:从柔性到超柔性(英文)显示文摘柔性薄膜有机半导体器件由于其轻便、柔性、有机半导体的可重复制备及易于进行功能性调节、以及低成本、大面积溶液加工等特性而受到广泛关注.其中,弯曲半径不超过1 mm的超柔性电子对可折叠/便携设备、可穿戴设备、表皮及植入式电子设备、三维表面贴合型器件以及仿生学等领域的发展至关重要.本综述首先简要介绍了从柔性到超柔性电子的发展史以及超柔性有机器件的设计.接着,聚焦于超柔性的有机场效应管、有机发光二极管、有机太阳能电池以及有机存储器等有机半导体功能器件领域的最新进展进行了总结评述. | 钱妍 张新稳 齐殿鹏 解令海 Bevita K.Chandran 陈晓东 黄维 | 2016 | Science China Materials2016，59，7： | 2 |
| 17 | Chlorophyll-based organic solar cells with improved power conversion efficiency显示文摘Chlorophylls(Chls), and associated chlorophyll derivatives, are one of the oldest, most versatile organic semiconductors found in nature. Herein, we present two easily semi-synthesized chlorophyll derivatives, namely, chlorin e6 trimethyl ester(Ce6Me3) and its copper complex(Cu–Ce6 Me3), as the p-type dopants for organic semiconductors and their impact in organic solar cells(OSCs). In our study, both Chls showed intense Soret and Q y bands in the UV-visible spectra, leading to an effect means for capturing solar light and energy. Chls also exhibited high carrier mobility owing to the partial formation of aggregates through the spin-coating process. Using Chls, we fabricated OSCs in both planar-heterojunction(PHJ) and bulkheterojunction(BHJ) solar cell configurations, together with C70/PC70 BM as electron acceptors. In PHJ solar cells, we received solar power conversion efficiencies(PCEs) of only 0.85% and 0.93% for Cu–Ce6 Me 3-and Ce6Me3-based devices, respectively, with the thickness of the donor layer at 5 nm. In BHJ cells, we achieved much higher PCEs of 1.53% and 2.05% for Cu–Ce6Me3 :PC 70 BM and Ce6Me3 :PC 70 BM respectively, where both blending ratios were set to 1:8. The improvement on PCE in BHJ cells may be attributed to the better charge separation increase at the donor–acceptor interface. | Shenghan Wang Shengnan Duan Yuwei Wang Chenglin Sun Xiao-Feng Wang Shin-ichi Sasaki | 2019 | Journal of Energy Chemistry2019，28，11： | 1 |
| 18 | Sulfur vs. tellurium: the heteroatom effects on the nonfullerene acceptors显示文摘The effect of chalcogen heteroatom variation on donor materials has been systematically investigated. However, this effect on acceptors has rarely been explored. Herein, nonfullerene acceptors BFPSP and BFPTP were reported by simply changing the chalcogen atoms from S to Te. The differences between BFPSP and BFPTP in light absorption, energy levels, excited-state lifetimes, energy loss, charge mobilities, morphology, and photovoltaic properties were systematically investigated to understand the heteroatom effects. More importantly, the electroluminescence spectra, external quantum efficiency of photovoltaics and TDDFTcalculations revealed that the triplet excited state(T1) in energy of BFPTP equals to the charge transfer(CT) state in PBDBT:BFPTP, which allows T1 excitons, generated by intersystem crossing, to split into free charges to contribute to the efficiency.This contribution provides a strategy for tuning the photophysical properties of nonfullerene acceptors and designing high performance triplet materials for OSCs. | Lei Yang Linqing Qin Yunxiao Xu Huotian Zhang Lei Lv Kepeng Chen Xinyu Sui Yangguang Zhong Yuan Guo Feng Gao Jianzhang Zhao Yuhao Li Xinfeng Liu Yuanping Yi Xinhui Lu Aidong Peng Hui Huang | 2019 | Science China Chemistry2019，62，7： | 1 |
| 19 | Electronic, optical, and charge transport properties of A-π-A electron acceptors for organic solar cells: Impact of anti-aromatic π structures显示文摘Organic solar cells based on acceptor-p-acceptor(A-π-A) electron acceptors have attracted intensive attention due to their increasing and record power conversion efficiencies. To date, almost all of the reported A-π-A electron acceptors are based on aromatic p structures. Here, we have investigated the impact of anti-aromatization of the p-bridges on the optoelectronic properties of A-π-A electron acceptors by(time-dependent) density functional theory. Our calculations show that besides the frontier molecular orbitals corresponding to the aromatic p-bridge based acceptors('aromatic' acceptors),additional and unique occupied and unoccupied frontier orbitals are found for the acceptors based on the anti-aromatic p-bridges('anti-aromatic' acceptors). Moreover, by tuning isomeric structures of the p-bridges(e.g., fusion orientations or linking positions of thiophene moieties), the optical excitation energies for the transition between the additional occupied and unoccupied levels turn to be close to or substantially lower with respect to those for the transition between the 'aromatic' frontier orbitals. The optical absorption of the 'anti-aromatic' acceptors is thus either stronger or broader than the 'aromatic'acceptors. Finally, the reorganization energies for electron transport are tunable and dependent on the p-bridge structures. These results indicate a great potential of 'anti-aromatic' electron acceptors in organic photovoltaics. | Yan Zeng Ruihong Duan Yuan Guo Guangchao Han Qingxu Li Yuanping Yi | 2019 | Chinese Chemical Letters2019，30，1： | 1 |
| 20 | Efficient organic solar cells achieved at a low energy loss显示文摘Organic photovoltaics(OPVs)have attracted much attention because of the advantages in low-cost and large-area fabrication and the great potentials in achieving flexible and semi-transparent devices(1)However,compared with inorganic and perovskite solar cells[2],OPVs show relatively low photoelectric conversion efficiencies,which is admittedly attributed to intrinsically low dielectric constants of organic materials[3]resulting in large energy losses(Eloss=EgqVoc,where Eg is the optical bandgap of the photoactive layer,Voc is the open-circuit voltage of photovoltaic devices and q is elementary charge). | Wenrui Liu Jianyun Zhang Shengjie Xu Xiaozhang Zhu | 2019 | Science Bulletin2019，64，16： | 1 |
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