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

• 来源期刊: 中国科学:化学（英文版）
• 年，卷（期）: 2018,（4）
• 页码范围: 427-436
• 页数: 10页
• 语种: 英文

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.