A-D-A型小分子电子给体光伏材料的端基修饰及其光伏性能  

Development of Benzodithiophene-Based A-D-A Small Molecules with Different Acceptor End Groups for Efficient Organic Solar Cells

作　　者：贾国骁 张少青 杨丽燕 何畅[2] 范慧俐[1] 侯剑辉[1,2] JIA Guoxiao;ZHANG Shaoqing;YANG Liyan;HE Chang;FAN Huili;HOU Jianhui(School of Chemical and Biological Engineering,University of Science and Technology Beijing,Beijing 100083,P.R.China;State Key Laboratory of Polymer Physics and Chemistry,Beijing National Laboratory for Molecular Sciences,Institute of Chemistry,Chinese Academy of Sciences,Beijing 100190,P.R.China)

机构地区：[1]北京科技大学化学与生物工程学院,北京100083 [2]高分子物理与化学国家重点实验室北京分子科学国家实验室中国科学院化学研究所,北京100190

出　　处：《物理化学学报》2019年第1期76-83,共8页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(2170040201);国家科技重大专项(2016YFC0700603);中央高校基本科研业务费专项资金(FRF-TP-17-009A1)资助项目~~

摘　　要：有机太阳能电池(OSCs)活性层中的给体材料主要包括共轭聚合物与有机小分子,由于有机小分子给体具有结构确定、易于提纯、重复性高等独特的优势,近年来受到研究工作者的广泛关注。本工作中,我们采取具有良好共平面性的三联苯并二噻吩(TriBDT-T)为推电子(D)中心共轭单元,分别以罗丹宁(RN)、氰基罗丹宁(RCN)和1,3-茚二酮(IDO)为拉电子(A)共轭端基,设计并合成了三种具有A-D-A型结构的小分子给体材料TriBDT-T-RN、TriBDT-T-RCN和TriBDT-T-IDO。我们对比研究了三种端基对其热分解温度、吸收光谱和分子能级等基本性能的影响,并分别将三种小分子给体与非富勒烯型受体材料IT-4F共混制备器件,详细研究了活性层形貌与光伏性能之间的关系。结果表明,不同的A型端基对小分子给体材料的光学性能、电化学性能、光伏器件中活性层的微观形貌以及能量转换效率(PCE)产生显著影响。基于TriBDTT-RN:IT-4F、TriBDT-T-RCN:IT-4F和TriBDT-T-IDO:IT-4F的光伏器件的能量转换效率分别为9.25%、6.31%和6.18%。In recent years, organic solar cells(OSCs) have attracted increasing attention, and the power conversion efficiency(PCE) of OSCs has markedly improved. To enhance the photovoltaic properties of OSCs, it is important to develop the donor materials in the light-harvesting layer, which mainly include conjugated polymers and small molecules(SMs). Compared with polymeric materials, small-molecule materials have been widely investigated for their superior characteristics, such as well-defined molecular structures that can provide good batch-to-batch reproducibility. In this work, we synthesized three SM donor materials with theacceptor-donor-acceptor(A-D-A) structure by employing the trialkylthienyl-substitutedbenzodithiophene(TriBDT-T) unit as the D-core unit, and rhodanine(RN), cyano-rhodanine(RCN), and 1,3-indanone(IDO) as the A end groups, respectively. The optical properties, molecular energy levels, and thermogravimetic characteristics of the three SMs were studied; moreover, the blend morphologies and photovoltaic properties of the devices by employing the non-fullerene(NF) acceptor, IT-4 F, were systematically investigated. The results showed that 1) the three SMs exhibit good thermal stabilities as evinced by thermogravimetric analysis(TGA), and all decomposition temperatures exceeded 410 °C; 2) They all exhibit strong and broad absorption in the visible light range(300–700 nm), and show similar molar extinction coefficients; 3) the HOMO levels are-5.47 eV,-5.54 eV, and-5.44 eV for RN, RCN, and IDO, respectively, implying the clear influence of the different end groups for the energy levels of the A-D-A-type SMs; the slight differences in the optical and electrochemical properties of the corresponding donor material could be attributed to the different electron-withdrawing ability of the A-type end groups. When studying the photovoltaic properties, interestingly, the RN:IT-4 F blend was found to form fibrillar-like aggregates with appropriate size, and the corresponding devices exhibited desirable short cir

关 键 词：小分子给体 端基修饰 有机太阳能电池 非富勒烯受体 A-D-A结构 

分 类 号：O646[理学—物理化学]