DFT investigation of optoelectronic and thermoelectric features of Ba2Ce(Sn,Pt)O6 double perovskites

Abstract

This study explores the geometric and thermodynamic stability, optoelectronic, and thermoelectric attributes of Ba2Ce(Sn,Pt)O6 double perovskites (DPs) through first-principles calculations. Both DPs exhibit stable cubic structures. Ba2CeSnO6 displays a bandgap of approximately 2.1 eV, indicating semiconductive behavior, while Ba2CePtO6 features a narrower bandgap of around 0.41 eV. This electronic behavior of both DPs is mainly influenced by the emergence of Ce-4f flat bands. Analysis of optical properties reveals absorption peaks at 3.4 eV for Ba2CeSnO6 and 1.2 eV for Ba2CePtO6, suggesting potential applications in visible and ultraviolet light optoelectronics. Additionally, the thermoelectric (TE) investigation demonstrates promising results, with high Seebeck coefficients (S) of 170 for Ba2CeSnO6 and 221 μV/K for Ba2CePtO6 at room temperature. The computed thermoelectric figure of merit (zT) exhibits a relatively stable trend for temperatures greater than 300 K, reaching 0.66 for Ba2CeSnO6 and 0.74 for Ba2CePtO6 at 800 K. This research provides valuable insights into the potential applications of these double perovskites in emerging technologies including visible light photonics and thermoelectric generators.