Thermal quenching of chromium photoluminescence in ordered perovskites. I. Temperature dependence of spectra and lifetimes

The temperature dependence of chromium photoluminescence spectra and lifetimes have been measured in ordered perovskite (Cs₂{NaYCl}₆$, ${K}₂NaScF₆, and K₂{NaGaF}₆) host crystals. Analysis of lifetime data yields thermal-quenching activation energies ΔE of 4250, 7270, and 9240{cm}^{{{-}}1}$, respectively. The Mott theory, applied to a single-configuration-coordinate, linear-coupling model with parameters inferred from emission spectra, fails by 20 orders of magnitude to explain the observed radiationless-transition rate.