Ba₂MgXO₆ (X = S, Se), Chalcogenide‐Based Double Perovskite Materials for Green Optoelectronics and Thermoelectric Applications

Chalcogenide‐based double perovskite materials have recently attracted attention of researchers because of their excellent properties and eco‐friendly nature. These compounds have proven to comprise better oxidation resistance, high‐temperature stability, and lower processing cost. In this report, the first‐principles study on chalcogenides double perovskites Ba2MgXO6 (X = S, Se) is described. It is shown that these perovskites can be synthesized, as they satisfy the structural, dynamical, and thermodynamical stability criteria. It is revealed that these double perovskites are inherently semiconductors in nature with low bandgap values, 0.33 eV for Ba2MgSO6 and 0.66 eV for Ba2MgSeO6 along Γ symmetry point. The absorption coefficient ≈105 cm−1 and the reflectivity below 12% in visible region are calculated. Therefore, the Ba2MgXO6 for solar cell applications is recommended. Also, on the basis of calculated larger values of figure of merit, these perovskites are proposed for thermoelectric applications at high temperatures.