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

Inverted perovskite solar cells (IPSCs) suffer from significant non-radiative recombination losses at the defective perovskite/C60 interface, limiting the efficiency and stability of perovskite/silicon tandem solar cells. Despite silicon oxide (SiOX) 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 SiOX layer without damaging the underlying perovskite. This SiOX interlayer not only chemically passivates under-coordinated Pb2+ 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 SiOX enables it to serve as a dense inner encapsulation, enhancing both light (ISOS-L-1) and thermal (ISOS-D-2I) device stabilities.