Stabilizing the Buried Interface via Inorganic-Organic Hybrid Layers for High-Performance Perovskite Photovoltaics

Abstract

Inverted perovskite solar cells, owing to their excellent stability and high compatibility with tandem technologies, have emerged as the most commercially promising new-generation photovoltaic technology. Self-assembled monolayers (SAMs) serve as crucial hole-transport materials and have driven device efficiencies beyond 27%. However, inherent issues such as molecular aggregation, non-uniform interfacial coverage, and poor wettability severely limit device performance and long-term stability. To systematically address these interfacial challenges, this study innovatively developed a hole-transport layer composed of colloidal silica nanoparticles and SAM molecules. This composite structure operates through multiple synergistic mechanisms: the abundant hydroxyl groups on the nanoparticle surfaces provide strong anchoring sites for SAM molecules, mitigating aggregation at the source and enabling the formation of a highly uniform and coherent hybrid interfacial contact; the constructed micro-nano rough interface significantly improves the wettability of perovskite precursors, guiding the formation of a high-quality light-absorbing layer. The resulting inverted perovskite solar cells achieved a power conversion efficiency of 27.35% and a fill factor of 86.77% (with a certified steady-state PCE of 26.92%), demonstrating significantly enhanced operational stability. This study provides a novel and practical solution for constructing efficient, stable interfaces for perovskite solar cells.