Comprehensive first principles to investigate optoelectronic and transport phenomenon of lead-free double perovskites Ba2AsBO6 (B[dbnd]Nb, Ta) compounds

Abstract

In the current work we studied the structural, elastics, electrical, optical, thermoelectric, as well as spectroscopic limited maximum efficiency (SLME) of oxide based Ba2AsBO6 (BNb, Ta) materials. All the calculations were performed using first-principles calculation by employing the WIEN2k code. We checked the stability in diverse forms such as optimization, phonon dispersion, mechanical, formation energy, cohesive energy, and thermal stability is computed. The semiconducting nature of these Ba2AsBO6 (BNb, Ta) systems is revealed by calculating the direct band gap values are 1.97 eV and 1.49 eV respectively. Additionally, we determined the optical properties which analyze the utmost absorption and transition of carriers versus photon energy (eV). Moreover, Ba2AsNbO6 has an estimated SLME of 32 %, making it an encouraging alternative for single-junction solar cells. Lastly, we studied the transport properties against temperature, the chemical potential for p-type and n-type charge carriers at various temperatures. At 300 K, the zT values are found to be 0.757 and 0.751 for Ba2AsBO6 (BNb, Ta) compounds respectively. Both materials were examined as having strong absorption patterns and an excellent figure of merit (ZT), indicating that materials are appropriate for daily life applications.