2D Perovskite Engineering Enables Robust Self-Assembled Monolayers for High-Performance Perovskite Solar Cells

Self-assembled monolayers (SAMs) are critical hole-selective contacts in inverted perovskite solar cells (PSCs), yet their practical implementation is hindered by desorption and aggregation during solution-based perovskite deposition. Here, we report a transient two-dimensional (2D) perovskite protection strategy using volatile propylammonium chloride, which temporarily shields SAMs from solvent-induced degradation and subsequently decouples during thermal annealing. This mechanism preserves the integrity of the SAM interface while enabling uniform crystallization of large-area perovskite films and efficient charge extraction. Consequently, PSCs achieve a power conversion efficiency (PCE) of 26.14% for 0.05 cm² devices, 23.27% for a 5 × 5 cm² mini-module, and 22.34% for a 30 × 30 cm² module (615.7 cm² active area). Notably, the large-area module retains 90% of its initial efficiency after 2000 h of continuous maximum power point operation, demonstrating both high performance and operational stability, highlighting a scalable route for reliable perovskite photovoltaics.