Perylene Diimide‐Based Electron‐Transporting Material for Perovskite Solar Cells with Undoped Poly(3‐hexylthiophene) as Hole‐Transporting Material

Abstract

Perylene diimide-based small molecules are widely used as intermediates of liquid crystals, owing to their high planarity and electron mobility. In this study, tetrachloroperylene diimide (TCl-PDI) was used as a small-molecule replacement for TiO₂ as electron-transporting material (ETM) for planar perovskite solar cells (PVSCs). Among hole-transporting materials (HTMs) for PVSCs, poly(3-hexylthiophene) (P3HT) gives the devices the highest stability and reproducibility. Therefore, PVSCs with the structure of indium tin oxide (ITO)/ETM/perovskite/P3HT/MoO₃ /Ag were used to evaluate the performances of new ETMs. A reference device with compact TiO₂ and P3HT gave a reasonable power conversion efficiency (PCE) of 12.78 %, whereas the PVSC with TCl-PDI as ETM gave an enhanced PCE of 14.73 %, which is among the highest reported values for PVSCs with undoped P3HT as the HTM. Moreover, TCl-PDI-based devices displayed higher stability than those based on compact TiO₂ , owing to the superior perovskite quality.