Strong hot-phonon bottleneck effect in all-inorganic perovskite nanocrystals

All-inorganic perovskite nanocrystals have attracted intensive research attention. We investigate the temperature-dependent photoluminescence spectra of all-inorganic perovskite nanocrystals under one-photon and two-photon excitation. The results indicate that there is a strong hot-phonon bottleneck effect in such nanocrystals, which is due to the relatively small ionic radius and large mass of inorganic cations Cs⁺ and the relatively small size of the polarons. This work elucidates the mechanism of long carrier lifetimes and high efficiency in perovskite photovoltaic devices and is helpful for the design and fabrication of high-performance optoelectronic devices.