Fine-tuning HOMO energy levels between PM6 and PBDB-T polymer donors via ternary copolymerization  

作　　者：Xiaojun Li Ruijie Ma Tao Liu Yiqun Xiao Gaoda Chai Xinhui Lu He Yan Yongfang Li 

机构地区：[1]Department of Chemistry and Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration&Reconstruction,Hong Kong University of Science and Technology,Clear Water Bay,Kowloon,Hong Kong,China [2]Hong Kong University of Science and Technology-Shenzhen Research Institute,Shenzhen 518057,China [3]Department of Physics,Chinese University of Hong Kong,New Territories,Hong Kong,China [4]Beijing National Laboratory for Molecular Sciences,CAS Key Laboratory of Organic Solids,Institute of Chemistry,Chinese Academy of Sciences,Beijing 100190,China [5]Laboratory of Advanced Optoelectronic Materials,College of Chemistry,Chemical Engineering and Materials Science,Soochow University,Suzhou 215123,China

出　　处：《Science China Chemistry》2020年第9期1256-1261,共6页中国科学（化学英文版）

基　　金：the Shenzhen Technology and Innovation Commission(JCYJ20170413173814007,JCYJ20170818113905024);the Hong Kong Research Grants Council(Research Impact Fund R6021-18)(16305915,16322416,606012,16303917);Hong Kong Innovation and Technology Commission(ITCCNERC14SC01,ITS/471/18);the National Natural Science Foundation of China(51573120,51973146,51820105003)。

摘　　要：To achieve high-efficiency polymer solar cells(PSCs),it is not only important to develop high-performance small molecule acceptors(SMAs)but also to find a matching polymer donor to achieve optimal morphology and matching electronic properties.Currently,state-of-the-art SMAs mostly rely on a donor polymer named PM6.However,as the family of SMAs continues to expend,PM6 may not be the perfect polymer donor due to the requirement of energy level matching.In this work,we tune the energy level of PM6 via the strategy of ternary copolymerization.We achieve two donor polymers(named PL-1 and PL-2)with upshifted HOMO(the highest occupied molecular orbital)energy level(compared with PM6),and can thus match with the SMAs with upshifted HOMO energy levels compared with Y6.These two copolymers exhibit slightly higher order of molecular packing and similar charge transport properties,which demonstrate that the method of ternary copolymerization can fine tune the HOMO level of donor polymers,while the morphology and mobility of the blend film remain mostly unaffected.Among them,the best device based on PL-1:Y6 exhibits power conversion efficiencies(PCEs)of 16.37%with lower open circuit voltage(Voc)but higher short circuit current voltage(Jsc)and fill factor(FF)than that of the device based on PM6:Y6.This work provides an effective approach to find polymer matches for the SMAs with upshifted HOMO levels.

关 键 词：polymer solar cells polymer donors random ternary copolymers tuning energy levels higher HOMO level acceptors 

分 类 号：TM914.4[电气工程—电力电子与电力传动] TQ317[化学工程—高聚物工业]