Effect of Fluorination on the Photovoltaic Properties of Medium Bandgap Polymers for Polymer Solar Cells  

作　　者：Huan Guo Wanbin Li Chunmei Chang Xia Guo Maojie Zhang 

机构地区：[1]Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, Jiangsu 215123, China

出　　处：《Chinese Journal of Chemistry》2018年第6期502-506,共5页中国化学（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China （Nos. 51503135, 51573120, 51773142 and 91633301）, the Priority Academic Program Development of Jiangsu Higher Education Institutions, the Jiangsu Provincial Natural Science Foundation （No. BK20150332）, the Natural Science Foundation of the Jiangsu Higher Education Institutions of China （No. 15KJB430027）, and the Ministry of Science and Technology of China （973 project, No. 2014CB643501）.

摘　　要：Fluorination of conjugated polymers is one of the effective strategies to tune the molecular energy levels and morphology for high efficient polymer solar cells （PSCs）. Herein, two novel donor-acceptor conjugated polymers, PffBT and PBT, based on bis（3,5-bis（hexyloxy）phenyl）benzo[1,2- b：4,5-b＇]dithiophene and benzo[c][1,2,5]thiadiazole （BT） with or without fluorination, respectively, were synthesized, and their photovoltaic properties were compared. The polymer PffBT based on fluorinated BT showed lower frontier energy levels, improved polymer ordering, and a well-developed fibril structure in the blend with PC71BM. As a result, the PSCs based on PffBT/PC71BM exhibit a superior power conversion efficiency （PCE） of 8.6% versus 4.4% for PBT-based devices, due to a high space charge limit current （SCLC） hole mobility, mixed orientation of polymer crystals in the active layer, and low bimolecular recombination.Fluorination of conjugated polymers is one of the effective strategies to tune the molecular energy levels and morphology for high efficient polymer solar cells （PSCs）. Herein, two novel donor-acceptor conjugated polymers, PffBT and PBT, based on bis（3,5-bis（hexyloxy）phenyl）benzo[1,2- b：4,5-b＇]dithiophene and benzo[c][1,2,5]thiadiazole （BT） with or without fluorination, respectively, were synthesized, and their photovoltaic properties were compared. The polymer PffBT based on fluorinated BT showed lower frontier energy levels, improved polymer ordering, and a well-developed fibril structure in the blend with PC71BM. As a result, the PSCs based on PffBT/PC71BM exhibit a superior power conversion efficiency （PCE） of 8.6% versus 4.4% for PBT-based devices, due to a high space charge limit current （SCLC） hole mobility, mixed orientation of polymer crystals in the active layer, and low bimolecular recombination.

关 键 词：benzo[c][1 2 5]thiadiazole conjugated polymers FLUORINATION polymer solar cells power conversion efficiency 

分 类 号：TQ225.261[化学工程—有机化工] TM914.4[电气工程—电力电子与电力传动]