Surpassing 13% Efficiency for Polythiophene Organic Solar Cells Processed from Nonhalogenated Solvent

• DOI: 10.1002/adma.202008158
• Publication Date: 2021-05-10T07:04:49Z
• Authors: Jingyang Xiao; Xiao'e Jia; Chunhui Duan; Fei Huang; Hin‐Lap Yip; Yong Cao
• Keywords: Polythiophene; Miscibility; Acceptor

Abstract Benefiting from low cost and simple synthesis, polythiophene (PT) derivatives are one of the most popular donor materials for organic solar cells (OSCs). However, polythiophene‐based OSCs still suffer inferior power conversion efficiency (PCE) than those based on donor–acceptor (D–A)‐type conjugated polymers. Herein, a fluorinated derivative, namely P4T2F‐HD, is introduced to modulate miscibility morphology bulk heterojunction (BHJ)‐active layer, leading significant improvement OSC performance. The Flory–Huggins interaction parameters calculated surface energy differential scanning calorimetry results suggest that P4T2F‐HD shows moderate with nonfullerene acceptor Y6‐BO (2,2′‐((2 Z ,2′ )‐((12,13‐bis(2‐butyloctyl)‐3,9‐diundecyl‐12,13‐dihydro‐[1,2,5]thiadiazolo[3,4‐ e ]thieno[2′,3′:4′,5′]thieno[2′,3′:4,5]pyrrolo[3,2‐g]thieno[2′,3′:4,5]thieno[3,2‐ b ]indole‐2,10‐diyl)bis(methanylylidene))bis(5,6‐difluoro‐3‐oxo‐2,3‐dihydro‐1 H ‐indene‐2,1‐diylidene))dimalononitrile), while poly(3‐hexylthiophene) (P3HT) very miscible Y6‐BO. As result, case forms desired nanoscale phase separation in BHJ film P3HT completely mixed film, as revealed by transmission electron microscopy (TEM) grazing‐incidence wide‐angle X‐ray scattering (GIWAXS). By optimizing cathode interface P4T2F‐HD:Y6‐BO films processed nonhalogenated solvents, new record PCE 13.65% demonstrated. This work highlights importance controlling D/A interactions achieving also demonstrates promising system potential cost‐effective photovoltaics.