Tailoring the infrared resonances of sulfide perovskites

Abstract

Perovskites are promising materials for photovoltaic and optoelectronic applications. In this study, we systematically investigated the electronic and optical characteristics of sulfide perovskites using first-principles density functional theory (DFT) and time-dependent DFT calculations. The calculated results demonstrate the sensitive dependence of the optical properties of sulfide perovskites on the crystal symmetry as well as the spin orbit coupling. Particularly, they result in changes in electronic states close to the Fermi level and photoabsorption anisotropy. As a key finding, sulfide perovskites are characterized by an intense and focused optical signature in the infrared region of the electromagnetic spectrum, crucial for infrared LEDs and optical communication. The spin-orbit coupling modifies the valence band maxima and conduction band minima and considerably boosts the infrared resonance. In addition to the fundamental interest, I anticipate that the results of this work help in the development of active optical devices based on sulfide perovskites.