Controlled Nucleation and Targeted Interface Modification in Wide-Bandgap Perovskite Solar Cells Based on Evaporation/Solution Two-Step Deposition

/CsBr templates, which can serve as preferential nucleation sites to facilitate the growth of high-quality perovskite films. By optimizing evaporation conditions and incorporating 2,3,4,5,6-pentafluorobenzylphosphonic acid (pFBPA) during the spin-coating process, we achieved enhanced crystallization kinetics of nucleation sites and improved perovskite film uniformity. Further interface modification with pFBPA and ethane-1,2-diammonium iodide induces targeted surface dipoles at both carrier transport layers/perovskite interfaces, which not only offers better band alignment and surface passivation at both interfaces but also creates an enhanced electric field to boost electron extraction. These advancements enabled a WBG (1.68 eV) perovskite solar cell (PSC) to achieve an impressive power conversion efficiency (PCE) among WBG (1.65-1.7 eV) PSCs based on evaporation-assisted deposition. This study provides fundamental insights into achieving conformal high-quality WBG perovskite films, offering a theoretical foundation for the development of efficient perovskite/silicon tandems.