Disentangling Dual Emission Dynamics in Lead Bromide Perovskite

摘要

Metal halide perovskites exhibit intriguing properties for optoelectronicand electronic applications. Understanding their intrinsic photoexcitationand band-tail dynamics is essential for exploring novel functionality andimproving device performance. This report addresses the band-tail luminescenceof lead bromide perovskite (APbBr_3) single crystals, where A ismethylammonium, formamidinium, and cesium. Using time-resolved photoluminescence(PL) spectroscopy, the dynamics of well-defined dual emissionpeaks are unambiguously resolved from the picosecond to the microsecondscale. Whereas the long-lived states exhibit similar recombination dynamicsat high temperatures, a clear, fast transition occurs between the high and lowenergy states at low temperatures, indicating direct communication betweenthese two states. These time-resolved PL spectra shed light on the intrinsicoptical properties of metal halide perovskites.