Proton Transfer Complex-Confined Self-Assembled Monolayer for Thermally Stable Inverted Perovskite Solar Cells

Abstract Carbazole-derived hole-selective self-assembled monolayer (SAM) contacts are indispensable for high-performance inverted perovskite solar cells. Nevertheless, self-aggregation and molecular desorption of SAM result in a fragile heterogeneous interface, severely hindering device reproducibility and stability. Here, we propose a proton transfer complex-confined strategy to address the interfacial spatial heterogeneity, thereby enhancing the dispersion and adsorption of SAMs. This achieves a multi-site coupling design at the buried interface, effectively preventing interface destabilization by thermal stress. Consequently, a champion efficiency of 26.23% is achieved, with an impressive fill factor (85.64%). These devices resist thermal degradation at 75 °C for 1368 h. Notably, the potential difference change of the target SAMs after thermal degradation at 150 °C is only 5.9 mV, confirming its interfacial chemical stability. The corresponding perovskite film withstands 100 thermal stress cycles (–60 °C ∼ 85 °C). This strategy also achieves higher photovoltaic performance at a lower temperature (240 K).