Anti-Stokes photoluminescence of perovskite CsPbBr$_3$ nanocrystals in a fluorophosphate glass matrix

The anti-Stokes photoluminescence (PL) of perovskite CsPbBr$_3$ nanocrystals in a fluorophosphate glass matrix has been found and experimentally studied upon optical excitation to the low-energy edge of the photoluminescence band. The intensity of anti-Stokes PL depends linearly on the pumping power and increases rapidly with increasing temperature. A simple three-level model is proposed that describes well the main regularities of the observed phenomenon.