Making benzotrithiophene derivatives dopant-free for perovskite solar cells: Step-saving installation of π-spacers by a direct C-H arylation strategy

Previously, benzotrithiophene (BTT)-based hole-transporting materials (HTMs) had to be doped with three chemical agents for high-efficiency perovskite solar cells (PSC). This work describes significant progress by which the first dopant-free BTT core-based HTM (YKP03) with EDOT spacers was readily accessed by step-saving direct C-H arylation. PSCs with dopant-free YKP03 showed promising efficiencies of up to 16.15% with potential long-term storage stability.