Oblique‐Angle Damage‐Free Evaporation of Silicon Oxide Electron‐Selective Passivation Contacts for Efficient and Stable Perovskite and Perovskite/TOPCon Tandem Solar Cells

Abstract Inverted perovskite solar cells (IPSCs) suffer from significant non‐radiative recombination losses at the defective perovskite/C 60 interface, limiting the efficiency and stability of perovskite/silicon tandem solar cells. Despite silicon oxide (SiO X ) being a common passivation material in the silicon industry with higher electron selectivity than conventional atomic layer‐deposited alumina, its application in IPSCs is limited by its tendency to damage sensitive perovskite during processing. Here, an oblique angle evaporation method is developed to deposit a conformal, ultra‐thin SiO X layer without damaging the underlying perovskite. This SiO X interlayer not only chemically passivates under‐coordinated Pb 2+ defects but also forms an n/n+ homojunction that provides effective field‐effect passivation, concurrently reducing recombination and enhancing electron selectivity. As a result, extending this strategy to two‐terminal monolithic perovskite/tunnel oxide passivating contact silicon tandem solar cells achieves a stabilized power conversion efficiency of 30.2%, representing one of the highest efficiencies reported for such tandems. More importantly, the robust inorganic nature of SiO X enables it to serve as a dense inner encapsulation, enhancing both light (ISOS‐L‐1) and thermal (ISOS‐D‐2I) device stabilities.