Side-chain modification of polyethylene glycol on conjugated polymers for ternary blend all-polymer solar cells with efficiency up to 9.27%  

作　　者：Zhenye Li Baobing Fan Baitian He Lei Ying Wenkai Zhong Feng Liu Fei Huang Yong Cao 

机构地区：[1]Institute of Polymer Optoelectronic Materials and Devices,State Key Laboratory of Luminescent Materials and Devices,South China University of Technology [2]Department of Physics and Astronomy,Shanghai Jiao Tong University

出　　处：《Science China Chemistry》2018年第4期427-436,共10页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China(51673069,91633301,51521002,21520102006);Guangdong Natural Science Foundation(2017A030306011);the Pearl River S&T Nova Program of Guangzhou(201710010021);Fundamental Research Funds for the Central Universities

摘　　要：With the rapid progress achieved by all-polymer solar cells(all-PSCs), wide-bandgap copolymers have attracted intensive attention for their unique advantage of constructing complementary absorption profiles with conventional narrow-bandgap copolymers. In this work, we designed and synthesized a wide bandgap ternary copolymer PEG-2% which has the benzodithiophene-alt-difluorobenzotriazole as the backbone and the polyethylene glycol(PEG) modified side chain. The PBTA-PEG-2%:N2200 can be processed with a non-chlorinated solvent of 2-methyl-tetrahydrofuran(MeTHF) for the binary all-PSC, which exhibits a moderate photovoltaic performance. In particular, the ternary all-PSCs that consisting an additional narrow bandgap polymer donor PTB7-Th can also be processed with MeTHF, resulting in an unprecedented power conversion efficiency(PCE)of 9.27%, and a high PCE of 8.05% can be achieved with active layer thickness of 240 nm, both of which are the highest values so far reported from all-PSCs. Detailed investigations revealed that the dramatically improved device performances are attributable to the well-extended absorption band in the photoactive layer. Hence,developing novel copolymers with tailored side chains, and introducing additional polymeric components, can broaden the horizon for high-performance all-PSCs.With the rapid progress achieved by all-polymer solar cells（all-PSCs）, wide-bandgap copolymers have attracted intensive attention for their unique advantage of constructing complementary absorption profiles with conventional narrow-bandgap copolymers. In this work, we designed and synthesized a wide bandgap ternary copolymer PEG-2% which has the benzodithiophene-alt-difluorobenzotriazole as the backbone and the polyethylene glycol（PEG） modified side chain. The PBTA-PEG-2%：N2200 can be processed with a non-chlorinated solvent of 2-methyl-tetrahydrofuran（MeTHF） for the binary all-PSC, which exhibits a moderate photovoltaic performance. In particular, the ternary all-PSCs that consisting an additional narrow bandgap polymer donor PTB7-Th can also be processed with MeTHF, resulting in an unprecedented power conversion efficiency（PCE）of 9.27%, and a high PCE of 8.05% can be achieved with active layer thickness of 240 nm, both of which are the highest values so far reported from all-PSCs. Detailed investigations revealed that the dramatically improved device performances are attributable to the well-extended absorption band in the photoactive layer. Hence,developing novel copolymers with tailored side chains, and introducing additional polymeric components, can broaden the horizon for high-performance all-PSCs.

关 键 词：all-polymer solar cells ternary blending wide bandgap conjugated polymers 

分 类 号：TM914.4[电气工程—电力电子与电力传动]