N-Annulated Perylene-Based Hole Transporters for Perovskite Solar Cells: The Significant Influence of Lateral Substituents

Graphical It's only lateral : Two N -annulated perylene-based hole transporters were reported for perovskite solar cells. In comparison to the bulky 2-hexyldecyl, the methoxyphenyl lateral substituent can induce stronger intermolecular π–π stacking and better connectivity of the intermolecular aggregate domains in the solid films, leading to improved hole mobility and power conversion efficiency of the perovskite solar cells. Perylene derivatives are a family of well-known organic electron-transporting materials with excellent photochemical and thermal stabilities, and have been widely used in various optoelectronic devices. In this work, two diphenylamine functionalized N -annulated perylenes are reported as hole-transporting materials (HTMs) for perovskite solar cells. Through joint theoretical and experimental studies, the HTM employing a methoxyphenyl lateral substituent is found to feature a closer stacking distance and better aggregate connectivity in the solid film than its analogue with the bulky 2-hexyldecyl lateral substituent, contributing to a higher hole mobility and a remarkably enhanced device performance of perovskite solar cells. This work demonstrates the significant influence of lateral substituents of HTMs on the intermolecular packing and solid microstructure, giving a clear insight on the molecular design of high-performance organic semiconductors.