物理化学学报2019，Vol.35Issue(3)：275-283,9.DOI:10.3866/PKU.WHXB201804231
第三组份端基对有机太阳能电池性能的影响
Effects of Terminal Groups in Third Components on Performance of Organic Solar Cells
摘要
Abstract
Ternary blends have been considered as an effective approach to improve power conversion efficiency (PCE) of organic solar cells (OSCs).Among them,the fullerene-containing ternary OSCs have been studied extensively,and their PCEs are as high as over 14％.However,all non-fullerene acceptor ternary OSCs are still limited by their relatively lower PCEs.In this work,we used wide-bandgap benzodithiophene-difluorobenzotriazole copolymer FTAZ as the donor,low-bandgap fused-ring electron acceptor (FREA),fused tris(thienothiophene) end-capped by fluorinated 1,1-dicyanomethylene-3-indanone (FOIC)as acceptor,and two medium-bandgap FREAs,indaceno-dithiophene endcapped by 1,1-dicyanomethylene-3-indanone (IDT-IC) and indacenodithiophene end-capped by 1,1-dicyanomethylene-3-benzoindanone (IDT-NC),as the third components to fabricate the ternary blends FTAZ:FOIC:IDT-IC and FTAZ:FOIC:IDT-NC,and investigated the effects of the third components on the performance of ternary OSCs.Both IDT-IC and IDT-NC are based on the same indacenodithiophene core but contain different terminal groups (phenyl and naphthyl).Relative to IDT-IC with phenyl terminal groups,IDT-NC with naphthyl terminal groups has extended ∏-conjugation,down-shifted lowest unoccupied molecular orbital (LUMO),red-shifted absorption and higher electron mobility.The binary devices based on the FTAZ:FOIC,FTAZ:IDT-IC and FTAZ:IDT-NC blends exhibit PCEs of 9.73％,7.48％ and 7.68％,respectively.Compared with corresponding binary devices,both temary devices based on FTAZ:FOIC:IDT-IC and FTAZ:FOIC:IDT-NC exhibit better photovoltaic performances.When the IDT-IC weight ratio in acceptors is 50％,the FTAZ:FOIC:IDT-IC temary devices exhibit the best PCE of 11.2％.The temary-blend OSCs yie ldsimultaneously improved open-circuit voltage (Voc),short-circuit current density (Jsc) and fill factor (FF) compared with the binary devices based on FTAZ:FOIC.The higher Voc is attributed to the higher LUMO energy level of IDT-IC compared with FOIC.The improved Jsc is attributed to the complementary absorption of FOIC and IDT-IC.The introduction of IDT-IC improves blend morphology and charge transport,leading to higher FF.The FTAZ:FOIC:IDT-NC system yields a higher PCE of 10.4％ relative to the binary devices based on FTAZ:FOIC as the active layer.However,the PCE of the FTAZ:FOIC:IDT-NC-based ternary devices is lower than that of the FTAZ:FOIC:IDT-IC-based temary devices.Compared with the binary devices based on FTAZ:FOIC,in FTAZ:FOIC:IDT-NC-based ternary devices,as the ratio of the third component increases,the Voc increases due to the higher LUMO energy level of IDT-NC,the FF increases due to optimized morphology and improved charge transport,while the Jsc decreases due to the overlapped absorption of FOIC and IDT-NC.The terminal groups in the third components affect the performance of the ternary OSCs.The lower LUMO energy level of IDT-NC is responsible for the lower Voc of the FTAZ:FOIC:IDT-NC devices.The red-shifted absorption of IDT-NC leads to the overlapping of the absorption spectra of IDT-NC and FOIC and lower Jsc.On the other hand,replacing the phenyl terminal groups by the naphthyl terminal groups influences the Π-Π packing and charge transport.The FTAZ:FOIC:IDT-NC blend exhibits higher electron mobility and more balanced charge transport than FTAZ:FOIC:IDT-IC,leading to a higher FF.关键词
稠环电子受体/非富勒烯受体/有机太阳能电池/端基效应/三元共混Key words
Fused-ring electron acceptor/Non-fullerene acceptor/Organic solar cell/Terminal-group effect/Ternary blend分类
化学化工引用本文复制引用
薛佩瑶,MARDER Seth R.,韩平畴,占肖卫,张俊祥,辛景明,RECH Jeromy,李腾飞,孟凯鑫,王嘉宇,马伟,尤为..第三组份端基对有机太阳能电池性能的影响[J].物理化学学报,2019,35(3):275-283,9.基金项目
The project was supported by the National Natural Science Foundation of China (21734001,51761165023,21504066,21534003),the Department of the Navy,U.S.(N00014-14-1-0580,N00014-16-1-2520),the Ministry of Science and Technology,China (2016YFA0200700) and the Natural Science Foundation,U.S.(DMR-1507249,CBET-1639429).国家自然科学基金(21734001,51761165023,21504066,21534003),美国海军部(N00014-14-1-0580,N00014-16-1-2520),中国科学技术部(2016YFA0200700)和美国自然科学基金(DMR-1507249,CBET-1639429)资助项目 （21734001,51761165023,21504066,21534003）
