Thermal‐Induced Cerium‐Doped Perovskite Solar Cells with a Fill Factor Exceeding 81%

Abstract

Hybrid organic–inorganic perovskites have attracted significant attention due to their remarkable optoelectronic properties and the feasibility of cost‐effective, high‐throughput manufacturing of perovskite solar cells (PSCs). The present p–i–n PSCs have poor film‐forming ability on poly[bis(4‐phenyl)(2,4,6‐trimethylphenyl)‐amine] (PTAA) film, resulting in a great number of defects within perovskite. Herein, the cerium ion (Ce3+) into the PTAA layer is successfully incorporated, which is thermal‐induced transferred onto the perovskite lattice and surface layer, by replacing Pb2+ in partial or uncoordinated metalsites and Ce3+–Ce4+ ion pair to suppress the bulk/surface defects, leading to a significantly enhanced power conversion efficiency (PCE). Systemically studies demonstrate that thermal‐induced Ce3+/4+‐doped MAPbI2.91Br0.09 thin film possesses superior film morphology with a uniform surface, suppressed nonradiative recombination, and enhanced crystallinity due to fewer bulk/surface defects. Moreover, PSCs by MAPbI2.91Br0.09/PTAA:xCe3+/4+ (x = 0.5 wt%) thin film exhibit suppressed charge carrier recombination and shorter charge carrier extraction time. As a result, PSCs by MAPbI2.91Br0.09/PTAA:xCe3+/4+ (x = 0.5 wt%) thin film exhibit PCE of 21.32% with significantly increased fill factor (FF) of 81.17% and long‐term stability. All these results indicate that the approach provides a facile way to incorporate rare‐earth ions into perovskites to boost the performance of PSCs.