Structural,photoluminescent, and dielectric properties of Eu3+-doped Ba0.7Sr0.3TiO3 thin films

Eu³⁺-doped Ba_0.7Sr_0.3TiO₃ thin films were prepared by a chemical solution deposition method and characterized by X-ray diffraction, field emission scanning electron microscopy, photoluminescence and dielectric measurements. The thin films were well crystallized with a pure perovskite structure. A contraction of the unit cell was observed upon incorporation of Eu³⁺ ions below 2 mol%, while an expansion occurred as the Eu³⁺ concentration was further increased above 2 mol%, indicating that Eu³⁺ ions with different concentrations occupied different lattice sites. Photoluminescence spectra showed two prominent transitions of Eu³⁺ ions at 594 nm (⁵D₀ → ⁷F₁) and 618 nm (⁵D₀ → ⁷F₂) upon excitation at 395 nm (⁷F₀ → ⁵L₆). There existed two quenching concentrations at 2 mol% and 4 mol% due to different lattice sites of the Eu³⁺ ions. We also investigated the dielectric properties of the thin films. Our study suggests that Eu³⁺-doped Ba_0.7Sr_0.3TiO₃ thin films have potential applications in multifunctional optoelectronic devices.