Crystallographic Alignment of α-FAPbI3 {100} Facets at the Buried Interface for Efficient Perovskite Photovoltaics

Abstract

At the SnO2/perovskite buried interface, the poorly controlled crystallization of black-phase α-FAPbI3 typically gives rise to a disordered interfacial facet configuration involving {100}, {110}, and {111} facets, which introduces a significant energetic barrier for electron injection and obscures the facet-dependent mechanisms governing carrier extraction and transport. Here, we identify buried-interface molecules that integrate a perovskite-interacting heterocycle with a substrate-anchoring carboxyl group, enabling the ordered alignment of {100} facets at the SnO2/perovskite interface. This crystallographic regulation reduces the interfacial electrostatic potential discontinuity, accelerates carrier extraction, and suppresses nonradiative recombination. As a result, the n-i-p perovskite solar cells achieve a power conversion efficiency of 26.65%, with a stabilized efficiency of 26.03%. Under maximum power point tracking in a nitrogen atmosphere at ∼50 °C under one-sun illumination, the devices retain over 91% of their initial efficiency after 2400 h of continuous operation, indicating enhanced operational stability.