Effect of furan π-bridge on the photovoltaic performance of D-A copolymers based on bi(alkylthio-thienyl)benzodithiophene and fluorobenzotriazole  

作　　者：Tinghai Yan Haijun Bin Yankang Yang Lingwei Xue Zhi-Guo Zhang Yongfang Li 

机构地区：[1]Beijing National Laboratory for Molecular Sciences,Key Laboratory of Organic Solids at Chinese Academy of Sciences,Institute of Chemistry,Chinese Academy of Sciences [2]School of Chemistry and Chemical Engineering,University of Chinese Academy of Sciences [3]Laboratory of Advanced Optoelectronic Materials,College of Chemistry,Chemical Engineering and Materials Science,Soochow University

出　　处：《Science China Chemistry》2017年第4期537-544,共8页中国科学（化学英文版）

基　　金：supported by the National Basic Research Program,Ministry of Science and Technology of China(2014CB643501);Beijing Nova program(Z171100001117074);the National Natural Science Foundation of China(91633301,91433117,21374124);the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB12030200)

摘　　要：The medium band gap donor-acceptor （D-A） copolymer J61 based on bi（alkylthio-thienyl）benzodithiophene as donor unit and fluorobenzotriazole as acceptor unit and thiophene as n-bridge has demonstrated excellent photovoltaic performance as donor material in nonfullerene polymer solar cells （PSCs） with narrow bandgap n-type organic semiconductor ITIC as acceptor. For studying the effect of n-bridges on the photovoltaic performance of the D-A copolymers, here we synthesized a new D-A copolymer J61-F based on the same donor and acceptor units as J61 but with furan n-bridges instead of thiophene. J61-F possesses a deeper the highest occupied molecular orbital （HOMO） level at -5.45 eV in comparison with that （-5.32 eV） of J61. The non-fullerene PSCs based on J61-F：ITIC exhibited a maximum power conversion efficiency （PCE） of 8.24% with a higher open-circuit voltage （Voc） of 0.95 V, which is benefitted from the lower-lying HOMO energy level of J61-F donor material. The results indicate that main chain engineering by changing n-bridges is another effective way to tune the electronic energy levels of the conjugated D-A copolymers for the application as donor materials in non-fullerene PSCs.The medium band gap donor-acceptor(D-A) copolymer J61 based on bi(alkylthio-thienyl)benzodithiophene as donor unit and fluorobenzotriazole as acceptor unit and thiophene as π-bridge has demonstrated excellent photovoltaic performance as donor material in nonfullerene polymer solar cells(PSCs) with narrow bandgap n-type organic semiconductor ITIC as acceptor.For studying the effect of π-bridges on the photovoltaic performance of the D-A copolymers,here we synthesized a new D-A copolymer J61-F based on the same donor and acceptor units as J61 but with furan π-bridges instead of thiophene.J61-F possesses a deeper the highest occupied molecular orbital(HOMO) level at-5.45 eV in comparison with that(-5.32 eV) of J61.The non-fullerene PSCs based on J61-F:ITIC exhibited a maximum power conversion efficiency(PCE) of 8.24%with a higher open-circuit voltage(V_(oc)) of 0.95 V,which is benefitted from the lower-lying HOMO energy level of J61-F donor material.The results indicate that main chain engineering by changing π-bridges is another effective way to tune the electronic energy levels of the conjugated D-A copolymers for the application as donor materials in non-fullerene PSCs.

关 键 词：nonfullerene polymer solar cells conjugated D-A copolymers furan π-bridges 

分 类 号：TM914.4[电气工程—电力电子与电力传动] O631[理学—高分子化学]