Multiexciton Lifetime in All-Inorganic CsPbBr₃ Perovskite\nNanocrystals

Abstract

A lot\nof research has been lately conducted on perovskites, which\nshow promising properties for many applications, ranging from optoelectronics\nto photovoltaics. Recently, a new class of perovskite nanocrystals\n(NCs) has been synthesized, namely all-inorganic cesium lead halide\nperovskite NCs (CsPbX₃, X = Cl, Br, I), showing high photoluminescence quantum yields (50–90%),\nnarrow emission bands, and tunable emission. In this study, we investigate\nthe ultrafast carrier dynamics in CsPbBr₃ perovskite NCs\nusing pump–probe transient-induced absorption spectroscopy.\nWe demonstrate that depending on the excitation fluence, hot carriers\nwith carrier temperatures up to 800 K are created upon photon excitation.\nWe also report, for the first time, lifetimes of higher order multiexciton\ncomplexes, next to that of the biexciton. These results have implications\nfor the application prospects of these materials for lasers, light-emitting\ndevices, and photovoltaic devices, among others.