Revealing the compositional effect on the intrinsic long-term stability of perovskite solar cells

Abstract

Understanding the role of individual cation and halide components in the intrinsic long-term stability of perovskite solar cells (PSCs) is of great importance to pursue devices with high efficiency and superior long-term stability simultaneously. In this work, we report a low dopant content (1%) doping strategy to reveal the role of individual bromide and methylammonium (MA) in the intrinsic operational stability of formamidinium lead iodide (FAPbI₃-based) PSCs. This strategy enables us to tune the trap density of perovskite films while keeping their apparent morphological and optical properties unchanged. Our results demonstrate that the incorporation of MA into FAPbI₃-based PSCs is harmful to their long-term stability due to defect-induced degradation. And Br incorporation is beneficial for enhancing the stability of FAPbI₃-based PSCs via suppressing the trap density in perovskite films. This work highlights the importance of defect management in improving the long-term operational stability of perovskite solar cells.