Effects of ZnI2 doping on the performance of methylammonium-free perovskite solar cells

作者：Yan, Lei; Li, Zhenchao; Niu, Tianqi; Xu, Xiang; Xie, Shenkun; Dong, Guanping; Xue, Qifan^*; Yip, Hin-Lap^*

来源：Journal of Applied Physics, 2020, 128(4): 043102.

DOI：10.1063/5.0012370

• PHOTOVOLTAIC PERFORMANCE
• CH3NH3PBI3 PEROVSKITE
• FORMAMIDINIUM
• EFFICIENT

Methylammonium (MA)-free perovskite solar cells (PVSCs) have obtained great attention recently, owing to their superior stability. However, there are still gaps in efficiency between MA-free PVSCs and MA-containing counterparts. Their stability still needs to be further enhanced for meeting commercial standards, especially the illumination stability. Here, we incorporate Zn2+ into perovskite thin films to passivate defects, successfully achieving a champion efficiency of 20.7% and reinforcing the stability of MA-free FA(0.9)Cs(0.1)PbI(3) PVSCs. This study reveals that Zn-doping can increase the grain size and contribute to modulate the crystallization process. Moreover, it is found that most of the Zn2+ aggregates at the grain boundaries passivating defects and, thus, effectively restrain the non-radiative recombination in the PVSCs. These findings provide a new way of realizing highly efficient and stable PVSCs.