Precisely-Controlled Co-Self-Assembled Monolayer for Improved Performance of Blade-Coated Perovskite Solar Cells

Abstract

Self-assembled monolayers (SAMs) have achieved remarkable success in the realm of inverted perovskite solar cells (PSCs). The integration of two distinct SAMs, referred to as co-SAM, significantly broadens the diversity within the SAM family and propels the enhancement of PSC performance. In this study, a co-SAM consisting of [4-(3,6-dimethoxy-9H-carbazol-9-yl)butyl] phosphonic acid (MeO-4PACz) and [2-(3,6-dimethyl-9H-carbazol-9-yl) ethyl] phosphonic acid (Me-2PACz) is sequentially deposited to achieve a precisely controlled nanostructure. It is unveiled that the initial deposition step governs the surface wettability, whereas the subsequent step dictates the energy level alignment. Leveraging this meticulously regulated co-SAM, the blade-coated PSC attains an impressive efficiency of 25.01%, retains 95.4% of its efficiency after 2500 h under illumination, and maintains 86.7% of its efficiency after ≈2000 h at 85 °C. This research delineates a novel pathway to facilitate the large-scale manufacturing of PSCs.