Effect of Ce doping on the multifunctional properties of BaTiO₃: From bandgap engineering to mechanical stability

Perovskite materials have garnered considerable interest for advanced electronic and optoelectronic applications. In this study, we investigate the structural, electronic, and optical properties of undoped and Ce-doped BaTiO 3 (Ba 1-x Ce x TiO 3 : x = 0.125, 0.25, 0.5) using first-principles calculations. Substitution of Ce at the Ba site leads to notable modifications in equilibrium lattice parameters, band structures, density of states, and optical responses. All optimized cubic structures align well with previously reported theoretical data. Ce doping induces a transition from an indirect to a direct bandgap at the Γ point and causes an upward shift in the Fermi level, characteristic of n-type semiconductor behavior. The bandgap widening, attributed to shifts in the conduction band minimum (CBM) and valence band maximum (VBM), enhances the material’s suitability for wide-bandgap applications. Optical analysis suggests strong potential for UV and deep-UV optoelectronics, power electronics, RF communication, and tandem perovskite solar cells. Elastic constant calculations confirm mechanical stability and reveal a mixed ionic–covalent bonding nature. Moreover, increasing Ce content lowers the Debye temperature, indicating altered thermodynamic behavior. Overall, Ce incorporation significantly enhances the multifunctional performance of BaTiO 3 , positioning it as a promising candidate for next-generation optoelectronic devices.