Isomeric selenasumanene-pyridine-based hole-transporting materials for inverted perovskite solar cells

Abstract

Conjugated small molecules have emerged as promising candidates for hole-transporting materials (HTMs) in p–i–n structured perovskite solar cells (PSCs). Although various structural designs of these molecules have been proposed, it remains unclear as to which configuration is truly optimal for enhancing device performance. Here, by designing two unique isomeric selenasumanene-pyridine-based HTMs, we successfully regulate the conformation of HTMs from parallel to orthogonal geometries. The architecture–functionality relationship stimulated by constitutional isomerism is explored through theoretical and experimental analyses. Specifically, the p–i–n PSCs based on orthogonal-structured HTMs feature an efficiency up to 25.05% (certified at 24.70%), representing a superior value for π-conjugated small molecule HTMs. Moreover, the unencapsulated devices retain over 96% of their initial efficiency after 1230 hours under light-thermal-operational conditions according to the ISOS-L-2 protocol.