Stirring-Time Control Approach to Manage Colloid Nucleation Size for the Fabrication of High-Performance Sn-Based Perovskite Solar Cells
Minghao Wang, Wei Wang, Yifan Shen, Juan Ma, Wei Shen, Kun Cao, Lihui Liu, Shufen Chen
Abstract
Colloidal nucleation is first observed to exist in a Sn-based perovskite solution, and its components and size are discovered to alter in real time with stirring time. Then, a simple stirring-time control approach is developed to manage the size of the colloids, and with continuous stirring for 3 days an optimal colloid with size <10 nm is confirmed to successfully form a continuous, dense, high-quality perovskite film. Herein, the colloids exist in the form of [SnI6]4– complete coordination compounds, with which a compact FA0.75MA0.25SnI3 perovskite film with reduced defects and enhanced crystallinity concentration is obtained as nucleation sites, and a planar inverted perovskite solar cell with a champion power conversion efficiency of 10.74% is eventually realized. This work provides a novel perspective to enhance perovskite film quality and thus device performance via controlling high-quality nucleation in precursor solution.