Effect of SiO2 shell on photoluminescence enhancement of Eu3+ doped nanophosphor based on monoclinic Y2O3

Surface SiO2 coating strategy was used to enhance the photoluminescent properties of Eu3+ doped nanophosphor based on monoclinic Y2O3. Laser-synthesized m-Y2O3:Eu3+ spherical nanoparticles with high crystallinity and diameter of ca. 18 nm were used as a core for the preparation of m-Y2O3:Eu3+@SiO2 core-shell structures. According to HRTEM and HAADF-STEM data, a thin SiO2 shell uniformly encapsulated the crystal core with a thickness of about 1.5 nm. The SiO2 shell increases the absolute photoluminescence quantum yield of Eu3+ at λ = 395 nm excitation from 14% to 68%. To the best of our knowledge, the obtained quantum yield exceeds the known values for Eu3+ doped oxide-based nanophosphors and is comparable to those of some other commercial red microphosphors. The SiO2 coating was shown to reduce the luminescence quenching effect associated with the annealing-induced migration of Eu3+ from the bulk to the surface of nanoparticles. The obtained results demonstrate that m-Y2O3:Eu3+@SiO2 core-shell nanoparticles with intense red luminescence have significant potential for use in LEDs, high resolution displays, bioimaging technologies and in other solid-state lighting applications.