Long-range hot carrier transport in lead-free cesium tin halide perovskite microplates

The carrier dynamics of lead-free cesium tin halide perovskites are crucial for evaluating their potential as substitutes for lead-based perovskites. Herein, we investigate the ultrafast transport of hot carriers in CsSnBr3 microplates synthesized via chemical vapor deposition. We observe a significantly prolonged hot carrier cooling process lasting ∼50 ps, due to the hot-phonon bottleneck effect and the formation of large polarons. By employing transient absorption microscopy, we detect a time-dependent diffusion coefficient of hot carriers initially reaching up to 257.8 cm2·s−1, leading to a long average travel distance of ∼600 nm. Subsequently, it reveals a remarkable equilibrium carrier diffusion coefficient ranging from 12.7 to 16.5 cm2·s−1. These findings establish a fundamental basis for designing and advancing lead-free perovskite-based optoelectronic applications involving hot carriers.