Cesium-Doped Ti ₃C ₂T _x MXene for Efficient and Thermally Stable Perovskite Solar Cells

Abstract

Ti₃C₂T_x MXenes have been shown to be a promising candidate for use in various applications. Herein, we prepared functionalized Ti₃C₂T_x MXene nanosheets doped with cesium (Cs) and introduced them into lead iodide (PbI₂) precursor solution for perovskite solar cells (PSCs) through a two-step deposition method. Our theoretical and experimental analysis revealed that Cs plays an important role in improving the perovskite crystallization and thus leading to enlarged crystal grains, long-lived carrier lifetimes, and reduced charge recombination as compared to the devices fabricated without and with undoped Ti₃C₂T_x MXene. PSCs integrated with Cs doped Ti₃C₂T_x MXene delivered a high photovoltaic efficiency of up to 21.57% with excellent thermal stability. The incorporation of Cs-Ti₃C₂T_x paves the way to further improve the photovoltaic performance and thermal stability of PSCs.