A Dynamic Anchoring Molecular Bridge Enables Robust Buried Heterojunction for Stable Perovskite Photovoltaics

ABSTRACT The performance of perovskite photovoltaics is critically governed by the buried interface quality. Conventional interfacial layers, such as self‐assembled monolayers (SAMs), often suffer from molecular aggregation, which compromises adhesion and promotes ion migration. To overcome this limitation, we introduce a dynamic anchoring molecular bridge, 6‐aminohexylphosphonic acid hydrochloride (AHPH). Its dual‐anchoring groups suppress SAM aggregation, while unbound molecules migrate during crystallization to guide the in situ formation of a low‐dimensional perovskite heterojunction. This bridge robustly connects the charge transport layer to the perovskite bulk, enhancing mechanical stability and concurrently suppressing halide/lead ion diffusion. Furthermore, AHPH templates perovskite crystallization, improving film quality through nucleation control and Ostwald ripening. This synergistic interfacial engineering strategy, centered on constructing a dynamic molecular bridge for a robust buried heterojunction, enables inverted perovskite solar cells with a champion efficiency of 25.7% and significantly improved operational stability.