Green-solvent-soluble, highly efficient dopant-free hole-transporting material for perovskite solar cells

Halogenated solvents (e.g. chlorobenzene and chloroform) are typically used for hole-transporting materials (HTMs) in perovskite solar cells (PSCs); however, their use should be avoided as they are known to be hazardous to the environment. Herein, we synthesized a nonhalogenated-solvent-soluble, dopant-free HTM, SF62. When depositing HTMs for PSCs, SF62 could be dissolved with a nonhalogenated and green solvent, ethyl acetate. It is one of the most common organic solvents and is known to have a low environmental impact. Non-doped-SF62-based PSCs exhibited higher power-conversion efficiency (18.6%) than doped 2,2 ',7,7 '-tetrakis(N,N-di-p-methoxyphenylamino)-9,9 '-spirobifluorene (Spiro-OMeTAD)-based ones (18.3%), with enhanced stability.

Automated summary

In this study, a nonhalogenated solvent-soluble HTM, SF62, was synthesized and successfully used in PSCs, resulting in higher power-conversion efficiency and enhanced stability compared to doped Spiro-OMeTAD-based ones.