Improving Performance and Stability of Planar Perovskite Solar Cells Through Passivation Effect with Green Additives

Perovskite solar cells (PSCs) have debuted as the photovoltaic devices with the most potential and progress is being made at an unprecedented pace. Meanwhile, additive engineering is continuously pushing the power conversion efficiency (PCE) and device stability to higher levels by passivating defects and regulating crystallization behaviors. Considering the scalable fabrication of PSCs in the following stage, seeking green additives for optimizing perovskites is extremely valuable and paramount. Herein, we pioneer a green additive engineering method using fumaric acid (FMAC) to optimize the three-cation perovskites to obtain highly efficient PSCs. FMAC not only optimizes crystallization behaviors to endow the perovskite films with a large grain size and few grain boundaries, but also forms a strong interaction with Pb2+/I- of the perovskites, thereby stabilizing the [PbI6](4-) octahedral framework of the perovskite crystal lattices and effectively passivating the surface defects. On this basis, FMAC improves the photoelectric properties of perovskites and in particular, suppresses the nonradiative recombination. Consequently, the PCE of PSCs incorporating FMAC rises to 20.48%, exceeding that (19.18%) of the pristine device. In addition, FMAC also enhances the stability of PSCs. Therefore, we provide a significant strategy using a green additive to enhance the photovoltaic performance of PSCs.