Study of mechanical, optoelectronic, and thermoelectric properties of Rb2ScAuZ6 (Z = Br, I) for energy harvesting applications

In the current article, the structural, mechanical, optoelectronic, and thermoelectric properties of Rb2ScAuZ6 (Z
= Br, I) have been predicted using the density functional theory (DFT) approach. The tolerance factor, phonopy,
and formation energy analysis validated the structural, dynamic, and thermodynamic stability of Rb2ScAuBr6
and Rb2ScAuI6, respectively. Likewise, the investigated elastic properties concluded that both materials exhibit
mechanical stability and possess ductile characteristics. The directional-dependent elastic moduli revealed the
anisotropy features. The indirect bandgaps determined by TB-mBJ approximation are 2.1 eV and 1.6 eV for
Rb2ScAuBr6 and Rb2ScAuI6, respectively. Optical absorption, reflectivity, refractive index, and dielectric constants
have been assessed in the energy range between 0 and 6 eV to ensure efficient absorption in the visible
spectrum. Both materials have appropriate optical parameters for utilization in photovoltaic systems. Further,
using the BoltzTraP code, the thermoelectric properties have been calculated to evaluate the thermoelectric
efficiency. Both perovskites have lower lattice and electronic thermal conductivity, a higher Seebeck coefficient,
and a higher figure of merit, making them ideal candidates for thermoelectric applications.