Mechanical, optoelectronic and thermoelectric response of oxide double perovskites Ca2VXO6 (X = In, Tl) for sustainable energy application

In this study, we computationally explored the structural, mechanical, electronic, optical and thermoelectric properties of Ca 2 VXO 6 (X = In, Tl) oxide double provskites using first-principles calculations within the framework of density functional theory. Both compounds crystallize in a highly symmetric cubic structure with space group F m 3 ¯ m (No. 225). The calculated tolerance factors within the acceptable range, along with the negative formation energies, confirm the structural and thermodynamic stability of the compounds. Mechanical property analysis indicates that both materials exhibits ductile behaviour, consistent with Pugh’s and Poisson’s ratios. Electronic calculations reveal that both materials are indirect bandgap semiconductors with bandgap energies of 2.36 eV and 2.32 eV, respectively, and exhibit p-type conductivity. Optical analysis shows strong absorption and high optical conductivity in the visible-ultraviolet region. Thermoelectric evaluations indicate favorable Seebeck coefficients and power factors, with the figure of merit (ZT) reaching 0.56 and 0.71 at 1000 K for Ca 2 VInO 6 and Ca 2 VTlO 6 , respectively. These results highlight the potential of Ca 2 VInO 6 and Ca 2 VTlO 6 as promising materials for renewable energy applications, particularly in optoelectronic applications such as solar cells, photodetectors, optical sensors, and transparent layers, as well as in thermoelectric energy conversion, including generators and cooling devices. • Ca2VXO6 (X = In, Tl) double perovskites show high structural and thermodynamic stability. • Mechanical analysis confirms ductile nature and mechanical stability. • Ca2VInO6 exhibits a 2.36 eV indirect band gap, while Ca2VTlO6 shows a slightly lower value of 2.32 eV. • Both compounds are indirect bandgap semiconductors with p-type conductivity. • Strong UV absorption and high optical conductivity are observed. • Thermoelectric analysis reveals ZT = 0.56 for Ca2VInO6 and ZT = 0.71 for Ca2VTlO6 at 1000 K.