苯并三氮唑类有机光伏材料研究进展

Research Advances on Benzotriazole-based Organic Photovoltaic Materials

数十年来,有机太阳能电池(organic solar cells,OSCs)的相关研究进展迅速,其能量转换效率从2000年的不足5%,发展至今已经超过18%,而这主要得益于给体和非富勒烯受体有机光伏材料的不断推陈出新.苯并三氮唑(benzotriazoles,BTA)作为一种经典的缺电子型杂环单元,伴随着有机光伏领域的兴起与发展,由BTA单元构筑的聚合物给体、小分子给体、非富勒烯小分子受体以及聚合物受体材料被不断地设计合成出来,特别是J系列聚合物给体材料和Y系列非富勒烯受体材料.伴随着材料体系的不断优化,相关的分子设计策略也得到更新与完善,以期从多角度对OSCs的性能有针对性的进行调控.本综述旨在通过介绍基于BTA单元的有机光伏材料的相关研究进展以及与之相关的分子设计策略,回顾BTA类光伏材料数十年来的发展历程,并展望其未来的发展前景.

Over the past two decades,organic solar cells(OSCs)have been developed rapidly with the power conversion efficiency rapidly rising from less than 5%to over 18%,which is mainly promoted by the development of various new donor and acceptor materials.As a typical electron-deficient penta-heterocycle,benzotriazoles(BTAs)derivates a variety of high-performance photovoltaic materials,including polymer donor,small-molecule donor materials,as well as non-fullerenes acceptor and polymer acceptor.Among them,the J series of polymer donors and Y series of non-fullerenes acceptors are typ-ical examples,and thus are specially highlighted in this review.Meanwhile,molecular design strategies of those BTA-based photovoltaic materials have also been discussed.It shows that donor-acceptor(D-A)conjugated strategy is still the most efficient thus far,where A units is the BTA unit or its derivatives,and D units commonly used in BTA-based photovoltaic mate-rials are benzodithiophene,benzodifuran,dithienosilole,indacenodithiophene,thiophene,etc.The D-A strategy is both ap-plied for donor molecules(with the molecular structure of D-A,D-π-A-π,D-A-D-A-D,etc.),and for acceptor molecules(with the molecular structure of A-D-A,A-π-D-π-A,A-DAD-A,etc.).By adjusting their molecular structures and/or pairing of differential D and A units,various properties such as absorption band and energy levels of molecules,as well as the mor-phology and charge carrier mobilities in OSCs can be well controlled.Furthermore,through side-chain engineering,such as flexible side-chains(alkyl,alkoxy,alkylthiol,alkylsilyl,etc.),conjugated side-chains(substituted-thiophene or benzene,etc.),electron-withdrawing groups(F atoms,Cl atoms,dicyanomethylene,etc.),their photovoltaic properties can be further regu-lated.Here,this review focuses on the research progress on BTA-based photovoltaic materials and related molecular design strategies developed in recent years,and also presents perspective on its future development.