Disentangling Dual Emission Dynamics in Lead Bromide Perovskite

Abstract

AbstractMetal halide perovskites exhibit intriguing properties for optoelectronic and electronic applications. Understanding their intrinsic photoexcitation and band‐tail dynamics is essential for exploring novel functionality and improving device performance. This report addresses the band‐tail luminescence of lead bromide perovskite (APbBr3) single crystals, where A is methylammonium, formamidinium, and cesium. Using time‐resolved photoluminescence (PL) spectroscopy, the dynamics of well‐defined dual emission peaks are unambiguously resolved from the picosecond to the microsecond scale. Whereas the long‐lived states exhibit similar recombination dynamics at high temperatures, a clear, fast transition occurs between the high and low energy states at low temperatures, indicating direct communication between these two states. These time‐resolved PL spectra shed light on the intrinsic optical properties of metal halide perovskites.