Exploring lead-free BaSrXWO 6 (X = Mg, Zn) double perovskites for UV-optoelectronic applications: a comprehensive first-principles study

Abstract The development of environmentally friendly perovskite optoelectronic devices depends on the selection of appropriate materials. Therefore, this study presents the design and first-principles investigation of lead-free BaSrXWO 6 (X = Mg, Zn) double perovskites as promising candidates for optoelectronic applications. These calculations confirm that both compounds crystallize in the cubic phase with space group F4̅3m. Structural analysis confirms the stability of both compounds in the cubic perovskite phase, as validated by the calculated Goldschmidt and octahedral tolerance factors. Furthermore, the calculated negative formation enthalpies further support the thermodynamic stability of both compounds. Both BaSrMgWO 6 and BaSrZnWO 6 materials exhibit a semiconductor nature with band gap values of 2.86 eV and 3.02 eV, respectively. The total and partial densities of states confirm the concentration of electrons within specific bands. The optical properties indicate strong absorption in the ultraviolet region, with absorption coefficients exceeding 8 × 10 5 cm −1 , along with moderate refractive index values of about 2.95. Various mechanical and thermodynamic parameters were evaluated and comparatively analyzed, confirming the mechanical strength and thermal stability of both compounds. These results provide a comprehensive and quantitative evaluation of BaSrXWO 6 double perovskites and support their potential as stable, lead-free materials for optoelectronic and related thin-film applications. As a result, these findings are expected to be a source of inspiration for future theoretical and experimental studies.