Determination of the electronic, dielectric, and optical properties of sillenite Bi₁₂TiO₂₀ and perovskite-like Bi₄Ti₃O₁₂ materials from hybrid first-principle calculations

Density functional theory calculation was conducted to determine the optoelectronic properties of bismuth titanate sillenite (Bi₁₂TiO₂₀) and perovskite-like (Bi₄Ti₃O₁₂) structures. The lattice parameters were experimentally obtained from Rietveld analysis. The density functional perturbation theory approach was used with the standard Perdew-Burke-Ernzerhof functional and screened Coulomb hybrid Heyd-Scuseria-Ernzerhof functional to investigate the electronic structure and absorption coefficient. Both compounds have good carrier transport properties, low effective hole and electron masses, high dielectric constant, and low exciton binding energy.