eScience (Nov 2021)
In situ growth of ultra-thin perovskitoid layer to stabilize and passivate MAPbI3 for efficient and stable photovoltaics
Abstract
The efficiency and stability of typical three-dimensional (3D) MAPbI3 perovskite-based solar cells are highly restricted, due to the weak interaction between methylammonium (MA+) and [PbI6]4-octahedra in the 3D structure, which can cause the ion migration and the related defects. Here, we found that the in situ-grown perovskitoid TEAPbI3 layer on 3D MAPbI3 can inhibit the MA+ migration in a polar solvent, thus enhancing the thermal and moisture stability of perovskite films. The crystal structure and orientation of TEAPbI3 are reported for the first time by single crystal and synchrotron radiation analysis. The ultra-thin perovskitoid layer can reduce the trap states and accelerate photo-carrier diffusion in perovskite solar cells, as confirmed by ultra-fast spectroscopy. The power conversion efficiency of TEAPbI3-MAPbI3 based solar cells increases from 18.87% to 21.79% with enhanced stability. This work suggests that passivation and stabilization by in situ-grown perovskitoid can be a promising strategy for efficient and stable perovskite solar cells.