Effect of Li, K and Be doping on phase stability, band structure and optoelectronic response of SrTiO3 perovskite for semiconductor devices: A computational insight

•A comprehensive study of influence of Li, K and Be doping on structural modification, bandgap tuning and optical response of SrTiO3.•The inclusion of K, Li and Be doping at Sr site in SrTiO3 alter the band gap from 1.792 eV to 1.888 eV, 1.897 eV and 1.620 eV, respectively.•The refractive index increases by doping as 2.49–4.6.•The absorption edge shifted to lower energy with Be doping.•Electronic structure and optical properties are strongly correlated.