A Self-Adaptive Buffer Layer with Photoswitchable Responses for Durable Perovskite Photovoltaics

S heterointerface, enabling adaptive interfacial reconstruction and efficient carrier extraction. When illumination ceases, ZnS returns to a relatively inert state, maintaining a physical and electric-field barrier against metal-halide interdiffusion. As a result, PSCs exhibit markedly improved durability, retaining over 97% of their initial power conversion efficiency after 7128 h of dark storage and 84.8% after 1632 h of continuous light soaking. The devices also show an enhanced tolerance to reverse-bias stress, establishing a self-regulated interfacial strategy for stable perovskite photovoltaics.