Exploring the impact of Ag, Au, and Cu doping on the electrical, optical, and thermoelectric properties of Sb₂S₃: an ab-initio study

We conducted a comprehensive study using DFT simulations of band structures and semi-classical Boltzmann transport equations to investigate the optoelectronic and transport properties of both pure and metal-doped antimony trisulfide (Sb₂S₃) crystals. To optimize the material’s performance, the doping process and associated technological parameters were carefully adjusted. The band structure was calculated using the Generalized Gradient Approximation (GGA). Our study revealed that intrinsic Sb₂S₃ has a well-defined band gap of 1.52 eV, confirming its semiconducting nature. However, when doped with Ag, Au, or Cu, the Sb₂S₃ crystals exhibited metallic behavior due to the disappearance of the band gap. The energy gap narrowed significantly as the concentration of these dopants increased. Additionally, we explored the origins of these bands through electronic density of states calculations. The optical dispersion spectra are calculated from the dielectric function spectra. Our findings demonstrate that doping Sb₂S₃ with Ag, Au, and Cu enhances its electrical conductivity, Seebeck coefficients, and optical absorption in both the visible and ultraviolet regions, highlighting its potential for advanced optoelectronic and thermoelectric applications. These results suggest that tailored doping of Sb₂S₃-based materials could be instrumental in enhancing the efficiency of energy-harvesting technologies.