Role of Anion Variation in Physical Properties of Novel Vacancy Ordered Ga2PtX6 (X = Br and I) for Solar Cell and Thermoelectric Applications

The objective of this research is to investigate the mechanical, structural, thermoelectric, and optoelectronic features of novel Ga₂PtX₆ (X = Br and I) double perovskite in order to determine prospective applications in solar energy production systems. The perovskites features have been estimated through first-principles computations depending on widely used Density Functional Theory and Tb-mBJ potential comprised in the WEIN2k package. According to the findings of TDOS and band structure, the energy indirect bandgaps of Ga₂PtBr₆ and Ga₂PtI₆ are found to be 1.88 eV and 0.84 eV, respectively. The estimated quantities of formation energy and Goldsmith’s tolerance factor demonstrate that the studied perovskites are thermodynamically and structurally stable. According to Pugh and Poisson ratio values, both examined compounds are ductile in nature. In terms of optical behavior, Ga₂PtI₆ exhibits the greatest absorption of the electromagnetic spectrum and dielectric function value in the visible and ultraviolet bands (101–523 nm), and for Ga₂PtBr₆ (106–397 nm) making it an attractive choice for optoelectronic and solar cell applications. The transport characteristics of the examined compounds were computed against chemical potential and temperature using the BoltzTrap algorithm. The transport properties suggest that Ga₂PtI₆ is the ideal material for use in thermoelectric devices because of its greater figure of merit, power factor, and electrical conductivity. Our findings show that Ga₂PtI₆ is the most promising choice for an absorptive layer in solar cells and thermoelectric device applications.