Multiexciton Lifetime in All-Inorganic CsPbBr₃ Perovskite Nanocrystals

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