Comprehensive Investigations on the Electronic and Transport Properties of Au 3 VX 4 (X = S, Se, Te) Compounds via DFT Study for Applications in TPV Cells

Narrow bandgap Au 3 VX 4 (X = S, Se, Te) sulvanite materials have been revealed through first-principles calculations, and their thermophotovoltaic (TPV) applications have simultaneously been demonstrated. The cubic Au 3 VX 4 (X = S, Se, Te) compounds exhibit thermodynamic, mechanical, and dynamical stability, as confirmed by the formation energy, stability criteria, and phonon dispersions, respectively. The studied Au 3 VS 4, Au 3 VSe 4, and Au 3 VTe 4 compounds show indirect bandgaps of 1.0, 0.89, and 0.55 eV, respectively, which fall within the optimal range for thermophotovoltaic (TPV) applications. The optical properties, such as dielectric constants, refractive index, optical conductivity, reflectivity, loss function, and absorption coefficients, have been investigated to understand the optical response of these ternary semiconductors. The observed bandgap of the Au 3 VX 4 is suitable for photon absorption in blackbody temperatures of 1625–2980 K. The single-junction TPV cells based on Au 3 VX 4 (X = S, Se, Te) compounds have been computed by a device transport model. The devices show remarkable efficiency in the range 9.73–10.87% at room temperature. The efficiencies obtained in this study highlight the promising future application of Au 3 VX 4 (X = S, Se, Te) compounds in the field of energy conversion.