Engineering an organic electron-rich surface passivation layer for efficient and stable perovskite solar cells

Surface passivation using organic molecules with appropriate charge distribution and geometric structure is crucial for achieving high-performance perovskite solar cells. Here, diphenylsulfone (DPS) and 4,4′-dimethyldiphenylsulfone (DMPS) with a conjugated structure are introduced at the perovskite and hole transport layer interface to investigate the impact of charge distribution on the interaction between the molecules and the perovskite surface. The presence of a methyl group in DMPS with a D-π-A structure optimizes charge distribution and enhances the passivation effect, resulting in an improved energy level alignment and facilitating hole transport. The perovskite solar cells using a DMPS treatment achieve an increase in power conversion efficiency to 23.27% with high stability, maintaining 92.5% of initial efficiency at 30% relative humidity for 1,000 h. This surface passivation strategy offers a promising avenue for enhancing the photovoltaic performance and environmental stability of perovskite solar cells, paving the way for future advancements in this domain.