Recent Progress of Surface Passivation Molecules for Perovskite Solar Cell Applications

Due to the solution processable nature, the prepared perovskite films are polycrystalline with considerable number of defects. These defects, especially defects at interface accelerate the carrier recombination and reduce the carrier collection. Besides, the surface defects also affect the long-term stability of the perovskite solar cells (PVSCs). To solve this problem, surface passivation molecules are introduced at selective interface (the interface between perovskite and carrier selective layer). This review summarizes recent progress of small molecules used in PVSCs. Firstly, different types of defect states in perovskite films are introduced and their effects on device performance are discussed. Subsequently, surface passivation molecules are divided into four categories, and the interaction between the functional groups of the surface passivation molecules and selective defect states in perovskite films are highlighted. Finally, we look into the prospects and challenges in design noble small molecules for PVSCs applications.