Thieno[3,2-b]indole–benzo[b]thieno[2,3-d]thiophen-3(2H)-one-based D–π–A molecules as electron transport materials for perovskite solar cells

Abstract

Four new compounds ISC 1–4 with a D–π–A structure, containing thieno[3,2-b]indole as an electron-donating unit and benzo[b]thieno[2,3-d]thiophen-3(2H)-one as an electron-accepting unit, were readily synthesized using a simple three-step protocol. The thermal stability, and optical and electronic properties of these materials were investigated. In thin solid films of ISC 1–4, the electron mobility measured using the conventional CELIV technique was in the range of 10⁻⁶ cm² V⁻¹ s⁻¹. The ISC 1–3 substances were found to be applicable as electron transport materials for perovskite solar cells. For the ISC 1 based PSC, the power conversion efficiency of 12.02% was demonstrated under AM 1.5 G irradiation.