Comprehensive study on structural, electronic, optical, elastic, and transport properties of natural mercury sulphohalides via DFT computation

Abstract

The Mercury Sulphohalides have attracted significant attention in the fields of solar cells and thermoelectric applications. This study delves into the fundamental characteristics, including structural, elasticity, electronic behavior, phonon stability, optical properties, and transport features of AgHgSZ (Z = Br, I) through computational simulations based on Density Functional Theory (DFT) using WIEN2k software. Meticulous calculations of the phonon band structure ensure dynamic stability. The semiconductor nature with indirect band gaps (1.833 eV and 1.832 eV) for Mercury Sulphohalides (Br, I), as revealed by their band structures, suggests diverse photovoltaic and transport applications. Mechanical assessments show stable ductility for AgHgSBr and brittleness for AgHgSI, along with anisotropy and resistance to scratching. Optical properties exhibit anisotropy and significant UV absorption. Analysis of effective masses, exciton binding energy, and exciton Bohr radius suggests low exciton binding energy and classification under Mott-Wannier excitons. Positive thermopower results indicate holes as the predominant charge carriers in AgHgSBr and AgHgSI materials. Moreover, essential thermoelectric factors are examined, revealing the compounds’ potential for thermoelectric applications. Notably, the figure of merit (ZT) at 300 K for AgHgSBr and AgHgSI are calculated to be 0.41 and 0.13, respectively. While these values are low at 300 K, they indicate promising potential for thermoelectric applications at higher temperatures. In summary, this investigation provides valuable understanding into the photovoltaic and thermoelectric properties of AgHgSZ (Z = Br, I) materials, potentially paving the way for further exploration in this domain.