Polymer donors based on alkyloxime‐substituted thiophene and 6‐undecylthiopheno[3,2‐b]thiophene for efficient organic solar cells

Abstract

AbstractTwo new copolymers (named PTO‐BO and PTO‐HD) with alkyloxime‐substituted thiophene (TO) as acceptor unit and 6‐undecylthiopheno[3,2‐b]thiophene spacer as π‐bridge were synthesized and applied in organic solar cells (OSCs) as electron donors. PTO‐HD with 2‐hexyldecyl side chains on TO moiety possesses more suitable phase separation, more efficient exciton dissociation and charge transportation, and less charge recombination than PTO‐BO with 2‐butyloctyloxime‐substituted thiophene in OSCs with Y6 as the acceptor. As a result, the OSCs based on PTO‐HD:Y6 achieved an optimal power conversion efficiency (PCE) of 13.89% with a Voc of 0.799 V, a Jsc of 22.74 mA cm−2, and a FF of 67.67% without additives, which is higher than that (12.29%) of PTO‐BO:Y6 OSCs.