Random Polymer Donor for High-Performance Polymer Solar Cells with Efficiency over 14%

Hang Yang^†, Yue Wu^†, Yingying Dong^†, Chaohua Cui^*,†（崔超华）, and Yongfang Li^†,‡

^† Key Laboratory of Organic Synthesis of Jiangsu Province, Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China

^‡ Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China

ACS Appl. Mater. Interfaces 2019, 11, 40339--40346

Constructing random copolymers has been regarded as an easy and effective approach to design polymer donors for state-of-the-art polymer solar cells (PSCs). In this work, we develop a naphtho[2,3-c]thiophene-4,9-dione-based copolymer PBN-Cl as a donor material for PSCs, and a moderate power conversion efficiency (PCE) of 11.21% is achieved with a relatively low fill factor (FF) of 0.615. We then incorporate a similar acceptor unit benzo[1,2-c:4,5-c′]dithiophene-4,8-dione (BDD) into the polymeric backbone of PBN-Cl to tune its photovoltaic performance, and a significantly higher PCE of 14.05% is achieved from the random polymer PBN-Cl-B80 containing 80% BDD unit. The enhanced PCE of the PBN-Cl-B80-based device mainly relies on the higher FF value, resulting from the improved charge mobility properties, reduced bimolecular and trap-assisted recombination, and more appropriate phase separation. The results demonstrate a feasible strategy to tune the photovoltaic performance of polymer donors by constructing a random polymer with a compatible component.

链接：https://pubs.acs.org/doi/10.1021/acsami.9b14133