Effect of Exciton-Phonon Coupling on the Temperature-Dependent Photoluminescence of CsPbX3 Nanocrystals in a Glass Matrix

Abstract For the first time, the temperature-dependent photoluminescence of CsPbX3 (X = Cl, Br, I) nanocrystals embedded in a fluorophosphate glass matrix is studied experimentally over a broad temperature range. We analyze the photoluminescence to investigate the role of exciton–phonon coupling in thermal quenching, broadening, and energy shift of the emission. The integrated intensity exhibits a two-step quenching behavior. The line width broadening is modeled by considering the contribution of optical phonon interactions. Above the critical temperatures, a sharp change in the temperature dependence of the peak energy is observed and associated with a phase transition in the nanocrystals. The linear energy shift at high temperatures is interpreted as a result of hydrostatic pressure exerted by the glass matrix due to thermal expansion mismatch. These findings provide insight into the exciton-phonon interactions and thermal stability of perovskite nanocrystals in a glass environment, which is crucial for their application in photonic and optoelectronic devices.