Enhanced optical and thermoelectric properties of Cu3Nb1−XVXS4 through chemical substitution: a DFT approach

This study presents theoretical investigations of a 2 × 2 × 2 supercell structure of Cu₃Nb_1−XV_XS₄ (X = 0.00, 0.25, 0.50, 0.75, 1.00) for optoelectronic and thermoelectric applications within DFT. Formation energy calculation reveals the energetical favourability of predicted compounds under chemical substitution. Electronic properties are investigated to comprehend the effect of V substitution on the Nb site. Results are then correlated with optical and thermoelectric properties. The study reveals a reduction in energy band gap with enhanced optical absorption coefficient in the order of 10⁵ cm⁻¹ and maximum ZT = 0.83 at 1100 K for certain substitution levels, revealing prospects of the investigated supercell for potential optoelectronic and thermoelectric devices. Systematic investigation into supercells’ properties is expected to provide a relevant approach towards future investigations on doping or chemical substitutional research.