Dual-Passivation Interfacial Engineering with Creatinol-O-Phosphate for High-Efficiency and Stable Perovskite Solar Cells

Tin oxide (SnO₂) is widely utilized as the electron transport layer (ETL) in <i>n-i-p</i> perovskite solar cells (PSCs) due to its excellent performance and ease of fabrication. However, defects on the surface of SnO₂ can impede carrier migration, and the chemical and physical properties of the ETL substrate can adversely affect the quality of the perovskite film grown on it, thus limiting the photovoltaic efficiency of PSCs. In this study, we introduced a bifunctional small molecule, creatinol-O-phosphate (COP), as an interlayer between SnO₂ and the perovskite layers. COP facilitates dual passivation by simultaneously addressing oxygen vacancies on the SnO₂ surface and undercoordinated Pb²⁺ ions within perovskite film, leading to an effective reduction in trap-state densities. This dual-passivation approach promotes perovskite grain growth, resulting in an alignment of grains perpendicular to the substrate and enhancing the overall crystalline quality of the perovskite film. Consequently, the power conversion efficiency (PCE) of the COP-modified PSC reached 24.45%, accompanied by improved storage stability. These findings underscore the potential of COP as a promising interface modifier for advancing the performance of PSCs.