Physical, optoelectronic and thermoelectric characteristics of double perovskite (Sr2ScBiO6) for green energy technology using ab initio computations

Abstract

This work presents the investigation of physical characteristics including structural, electronic, elastic, optical and thermoelectric, of the double perovskite (DP) oxide Sr₂ScBiO₆ with the aid of the FP-LAPW method, dependent on DFT combined with BoltzTraP code. To incorporate the inclusion of exchange as well as correlation effects, approximations like LDA and three different forms of GGA [PBE-GGA, WC-GGA & PBEsol-GGA] are applied. The mBJ-GGA method including spin-orbital coupling (SOC) & not including SOC was utilised in this investigation and it was carried out in the WIEN2k code. In addition, the TB-mBJ exchange potential analysis classified Sr₂ScBiO₆ as having a p-type semiconducting nature with an indirect bandgap value of 3.327 eV. Additionally, the mechanical properties analysis and the related elastic constants demonstrate the anisotropic nature of Sr₂ScBiO₆ with decent mechanical stability. Apart from that, the Sr₂ScBiO₆ was considered a brittle non-central force solid with dominant covalent bonding. The varying optical parameter evaluations highlighted the potential use of Sr₂ScBiO₆ in visible-light (vis) and ultraviolet (UV)-based optoelectronic devices. Moreover, the semiconducting nature of Sr₂ScBiO₆ was verified through its thermoelectric response, which revealed that the charge carriers mostly consist of holes. Over a wide temperature range (100–1200 K), several transport metrics like the Seebeck coefficient (S), electrical conductivity (σ/τ), thermal conductivity (κ/τ), and power factor (PF) are investigated. An optimal value of figure of merit (ZT) ∼ 0.62 at T = 1200 K is accomplished. The extremely lower value of thermal conductivity as well as higher electrical conductivity leads to a higher figure of merit of the investigated system. The Sr₂ScBiO₆ verified a high ZT value, confirming that the material would be beneficial in renewable energy and thermoelectric (TE) applications.