First-principles study of potassium-based novel chalcogenide materials for optoelectronic and thermoelectric devices

Abstract

The structural, electronic, optical, and thermoelectric natures of potassium-based ternary KAuY (Y = S, Se, and Te) materials are studied by employing density functional theory calculations. The LDA and PBE-GGA approximations were used to properly address the strongly correlated electron complexes. The ground-state energies, cohesive energies, and specifically the computed formation energy calculation predicted their stable nature. The calculated electron-effective mass of KAuTe was lower as compared to KAuS and KAuSe suggesting the presence of non-uniformity in energy bands at the conduction band minimum (CBM). The broader energy band gaps display the existence of firmly covalent bonds. The computed band structures calculation well supports their density of states calculations and validates the semiconductor nature of these materials. Moreover, optical constants such as the two components of the complex dielectric function, energy loss functions, absorption coefficients, reflectivity, and refractive index spectra are calculated and also explained for their potential usage in optoelectronic devices. The vital thermoelectric features are computed that suggest the studied material systems’ potential in the thermoelectric application. Principally, the present work would aid in the advancement of integrated and diverse semiconductors for high technological devices.