Chemical Vapor Deposition of FACs‐Perovskite on Asymmetric Self‐Assembled Molecules Enabled Efficiency of 19% for Semitransparent Solar Cells

Low‐pressure chemical vapor deposition (CVD) is a highly promising technique for perovskite photovoltaics commercialization. However, the device performance is constrained by relatively poor film quality. Herein, we regulate the growth process of perovskite by designing and synthesizing a novel asymmetric small molecule hole transporting material substrate based on an indolocarbazole core, namely (2‐(12‐phenylindolo[2,3‐a]carbazol‐11(12H)‐yl)ethyl)phosphonic acid (CPP‐2PACz). The feature of a large dipole within CPP‐2PACz facilitates the formation of a dense transporting layer, which slows down the reaction rate of the CVD process, resulting in perovskite films with larger grain sizes, improved interfacial energy level alignment, and more efficient charge transfer at the interface. As a result, champion efficiencies of 21.0% and 19.0% have been achieved in opaque and semitransparent perovskite solar cells, respectively. Moreover, the semitransparent PSCs retained ~ 90% of their initial performance after 800 h of continuous operation under the ISOS‐L‐1 protocol. Furthermore, we achieve a champion efficiency of 16.8% for semitransparent mini‐modules.