Rearranging cations on B sites to modify luminescence in layered-perovskite-like La3Ti2TaO11:Eu3+ ceramic phosphors

Abstract Compounds with the layered perovskite-like structure are well-known engineering materials because of the multifunctionality. In this work, a novel La3-xEuxTi2TaO11 (0 ≤ x ≤ 0.45) solid-solution with a typical layered perovskite-like structure was synthesized via the traditional solid-state reaction ceramic technique. The optimal emission happened in La3-xEuxTi2TaO11 (x = 0.3). To modify the luminescence properties, La2.7Eu0.3Ti2-5y/4Ta1+yO11 (y = 0.04, 0.05, 0.08, 0.1, 0.12, 0.14) phosphor was developed via stoichiometric alteration of (Ta5+→Ti4+) in “B” sites. The research motivation is on the fact that the framework distortion due to cation-disorders is an efficient method to modify the luminescence and improve the thermal stability of a rare earth ion (RE)-activated phosphor. The phase formations were conducted by XRD measurements and Rietveld refinements. The morphology was characterized by SEM and EDS. The luminescence properties such as luminescence, emission excitation wavelength, and decay lifetimes showed a dependence on the distortion of the framework. Cation alteration of (Ta5+→Ti4+) in La3-xEuxTi2TaO11 (x = 0.03–0.45) greatly modified the red-luminescence activities, such as improved efficiency, pure red chromaticity, and thermal stability. The excess of Ta5+ on Ti4+ sites bring about the distortion of octahedron surrounding resulting in intensive changes in the crystal-field environment around Eu3+ activators. The framework distortion due to substitutions of multiple cations is effective to enhance the emission efficiencies and thermal stability of RE3+-activated phosphors. The cation-disorder was discussed via luminescence features in 5D0→7F0 transition region. The results are helpful to introduce Eu3+ as a probe for rare-earth dopant site microstructure in phosphor materials.