Comprehensive analysis of structural, electronic, optical, and thermoelectric properties of X2PtCl6 (X = K, Cs, Rb): A first-principles DFT study

Abstract

Comprehensive analysis of X₂PtCl₆ (X = K, Cs, Rb) is presented through a first principle approach. We have explored the structural, electronic, thermoelectric and optical properties of these compounds. All the compounds exhibit direct band gaps at Γ symmetry point. The bandgap values of 1.52 eV, 1.49 eV and 1.39 eV were observed for Rb₂PtCl₆, Cs₂PtCl₆, and K₂PtCl₆, compositions respectively. Highest ZT values of 0.31 was observed around 900 K. This enhancement in TE properties corresponds to the optimal band gap and large negative Seebeck coefficient values obtained through systematic replacement of Rb with K. Dielectric constant graphs show the majority of the peaks were observed in the visible and Ultraviolet regions. Other promising optical properties were observed which include high absorption coefficient and optical conductivity and low reflectivity (about 1–15 %). Overall, this study shows the potential of these compounds for applications like solar cells and waste heat conversion devices.