Optoelectronic Properties of Chalcogenide Perovskites by Many-Body Perturbation Theory

TL;DR

This paper investigates the electronic and optical properties of chalcogenide perovskites AZrS3 using advanced theoretical methods, revealing their potential for efficient, stable, and non-toxic photovoltaic applications.

Contribution

It provides a detailed theoretical analysis of AZrS3 perovskites' optoelectronic properties using DFT and MBPT, including excitonic effects and efficiency estimates.

Findings

Higher exciton binding energy compared to halide perovskites.

Presence of stable charge-separated polaronic states.

High estimated maximum efficiency for photovoltaic applications.

Abstract

Chalcogenide perovskites have emerged as non-toxic and stable photovoltaic materials, acting as an alternative to lead halide hybrid perovskites having similar optoelectronic properties. In the present work, we report the electronic and optical properties of chalcogenide perovskites AZrS$_3$ (A=Ca, Sr, Ba) by using the density functional theory (DFT) and many-body perturbation theory (MBPT viz. G$_0$W$_0$ and BSE). This study includes excitonic analysis for the aforementioned systems. The exciton binding energy (E$_\textrm{B}$) is found to be larger than that of the halide perovskites, as the ionic contribution to dielectric screening is negligible in the former. We also observe a more stable charge-separated polaronic state as compared to that of the bound exciton. Finally, on the basis of direct gap and absorption coefficient, the estimated spectroscopic limited maximum efficiency (SLME) of the solar cells is large and suggests the applicability of these perovskites in photovoltaics.