Tungsten Oxide quantum dots-loaded Carbon Nitride Interlayer for Advancing Perovskite Solar Cells Performance

Abstract

The efficiency of single-junction Perovskite solar cells (PSCs) has approached the theoretical Shockley-Queisser limit; however, interfacial defects and charge carrier recombination remain critical challenges hindering further performance improvements. Herein, we introduce a novel composite material-tungsten oxide quantum dot/carbon nitride (WCN)-introduced at the interface between the electron transport layer (ETL) and the perovskite layer. This molecular design effectively enhances electron transport capability, passivates interfacial trap states, and optimizes energy level alignment. Furthermore, the resulting modified molecular layer inhibits the adverse interfacial reaction by preventing direct contact between the SnO2 ETL and the perovskite. The resulting PSCs fabricated with WCN interfacial modification layer achieve a power conversion efficiency of 23.92 % with an excellent long-term stability by maintaining >85 % of their initial efficiency after 1,500 h of ambient storage without encapsulation. This approach offers a promising strategy for advanced interface design, simultaneously improving charge extraction and defect passivation, thereby facilitating rational materials development and advancing the commercialization potential of PSCs.