Tuning Optical and Thermoelectric Response of Strontium Oxide with Ba Substitution for Photovoltaic and Optoelectronic Applications

SrO is a wide band gap material with potential thermoelectric, optical, and energy storage applications. While its properties are well-studied, the impact of strategic doping with elements like barium to enhance its functional characteristics remains less explored. This work employs density functional theory and experimental synthesis to investigate Ba-substituted SrO. All compositions maintain a cubic crystal structure with space group 225 Fm3m, while the incorporation of Ba reduces grain size and porosity. Electronic structure analysis reveals a reduction in band gap and a shift to n-type conductivity. PDOS spectra bring new electronic states with their 5d orbitals contributing significantly to and hybridising into the O-2p valence band manifold. The thermoelectric performance shows enhanced electrical conductivity, though the overall figure of merit is highest for highly doped compositions. The study concludes that Ba substitution effectively tunes the structural, electronic, and thermoelectric properties of SrO, making these modified compositions promising for photovoltaic and optoelectronic applications.