Impact of tin doping on charge carrier dynamics of a two-dimensional lead halide perovskite

Compositional engineering and doping of lead halide perovskites (LHPs) have emerged as promising methods to adjust the optical properties of these materials. Tin (Sn) doping, in particular, proves effective in achieving tunable bandgaps, enhanced stability, high defect tolerance, and improved transport properties. However, the impact of tin doping on the photophysical properties of two-dimensional (2D) LHPs remains largely unexplored. This study investigates the optical properties, including excited state properties, of a Sn-doped 2D perovskite, utilizing various spectroscopic techniques. Our femtosecond transient absorption measurements reveal alterations in charge carrier dynamics within the 2D perovskite due to Sn doping. The doping leads to a significant reduction in charge carrier trapping, resulting in slower carrier recombination. Furthermore, Sn doping reduces the exciton binding energy, consequently decelerating exciton-exciton annihilation in the Sn-doped perovskite.