Structural, microstructural characterization and luminescence spectroscopy of europium-doped strontium titanate prepared by the sol-gel method

Abstract

In this work, we report on the polycrystalline Sr1-3x/2EuxTiO3, x = 0.01–0.07 materials prepared by the sol-gel route and their optical properties. The Sr1-3x/2EuxTiO3 powders calcined at 1000 °C showed a microstructure consisting of nanograins with average particle size decreasing from 86.32 nm to 51.87 nm with the increase of Eu amount from 1 at% to 7 at% Eu, as revealed SEM and TEM investigations. Optimized sintering conditions of Eu-doped SrTiO3 ceramics (1400 °C, 4h in air) led to materials with a single phase of cubic SrTiO3. The high purity and uniform distribution of the chemical elements of as-fabricated SrTiO3 doped with Eu guaranteed good optical properties. The emission of the Eu3+ ion mainly occurs for the transitions from the 5D0 level to the levels of the 7Fj (j = 1, 2) term, more precisely, the 5D0 → 7F2 electric dipole transition (∼615 nm) or the 5D0 → 7F1 magnetic dipole transition (∼595 nm). The CIE coordinates of all samples calculated from the emission spectra obtained under the 395 nm and 465 nm excitation wavelength are located in the orange-red region. Therefore, this europium-doped SrTiO3 phosphor is a promising candidate for application as a red-emitting component in solid-state light sources.