Theoretical study on electronic, optical, magnetic and photocatalytic properties of codoped SrTiO3 for green energy application

Motivated by the large scientific interest in development of double cation doping of SrTiO 3 (STO) within the last years aiming to improve the water-splitting activity, electronic and ionic conductivity of STO, we study the effect of (La, X) and (Y, M) codoping (X = Al/Sc/Cr/Mn/Fe/Co/Ni/Mo, and M = Al/Cr/Mo) on the structure, electronic, magnetic, optical and photocatalytic properties (for water-splitting and CO 2 reduction) of STO using spin-polarized hybrid density functional theory. In most considered cases, the X and M monodoping reduces the bandgap of STO more than the (La, X) and (Y, M) codoping, except for the case of (La, Ni) codoping. We found out La-/Y-doping, and (La/Y, Al)-/(La, Sc)-codoping cannot improve the conductivity of STO, while other monodopants and codopants can increase it. Our calculations have revealed that the best suited candidates for mono-/co-doped STO-based photocatalysts are Fe-/(La, Ni)-STO. Furthermore, we disclosed Fe-/Mn-/(La, Mn/Fe/Ni)-STO could be appropriate for spintronic applications. • Electronic, optical, and photocatalytic properties of synthesized codoped SrTiO3 structures are investigated by hybrid DFT. • All monodoped structures have smaller bandgaps than the codoped ones, except for (La, Ni)-doped SrTiO3. • We demonstrate all codopants considered improve the conductivity of SrTiO 3 , except the (La/Y, Al) and (La, Sc) ones. • The Fe monodopant and (La, Ni) codopants are the best suited for enhancement of the SrTiO 3 photocatalytic properties. • The Fe and Mn monodoped, and (La, Mn/Fe/Ni) codoped structures can be useful for spintronic applications.