Electronic structure, reflectivity and X-ray luminescence of MAPbCl₃ crystal in orthorhombic phase

This study provides a comprehensive analysis of the electronic structure, reflectivity, and luminescent spectra of the organic-inorganic, metal-halide MAPbCl₃ perovskite, which has considerable potential for various optoelectronic applications. Using density functional theory (DFT) calculations, we investigated the electronic structure of MAPbCl₃ and interpreted the key features of its reflectivity spectra across a wide energy range from 3 to 10 eV. The reflectivity spectra reveal prominent excitonic features at 3.22 eV near the absorption edge and additional optical transitions at higher energies, highlighting the material's intricate electronic structure. Furthermore, we examined the temperature dependence of radiative decay dynamics under high-energy radiation through X-ray luminescence spectra and decay time measurements. We observe emission from free and bound excitons with an exceptionally short decay time (≤ 1 ns) and significant thermal quenching at low temperatures (100 K) in the 385-430 nm range. These findings underline the importance of continued exploration of optoelectronic properties of the material to enhance its performance in practical applications.