Key Words:X ray photoelectron spectroscopy;Electron diffraction - Electrons - High resolution transmission electron microscopy - Luminescence - Phosphors - Photoluminescence spectroscopy - Scanning electron microscopy - Shells (structures) - Silica - Spectrometers - Temperature - X ray diffraction;Core shell structure - Energy dispersive spectrometers - LaPO4:Eu^3+ - Luminescence properties - Selected area electron diffraction - SiO2 - Ultra violet excitation - Wet chemical route
Abstract:SiO<inf>2</inf>@LaPO<inf>4</inf>:Eu³⁺core-shell phosphors have been successfully synthesized by a one-step and economical wet-chemical route at low temperature. The as-obtained products were characterized by means of photoluminescence spectroscopy (PL), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). The SEM, EDS and XPS analysis indicate that SiO<inf>2</inf>@LaPO<inf>4</inf>:Eu³⁺core-shell phosphors can only be synthesized in a pH range of 8-11 and the possible mechanism has been proposed. The XRD results demonstrate that the structure of LaPO<inf>4</inf>:Eu³⁺layers is transferred into monoclinic phase from hexagonal phase after annealing at 800°C for 2h. The SiO<inf>2</inf>@LaPO<inf>4</inf>:Eu³⁺phosphors show strong orange-red luminescence under ultraviolet excitation. The relative emission intensity of Eu³⁺increases with increasing the annealing temperature and the number of coating cycles, and the optimum concentration for Eu³⁺was determined to be 5mol% of La³⁺in SiO<inf>2</inf>@LaPO<inf>4</inf>phosphors.<br/> © 2015 Elsevier Ltd.
Volume:83
Issue:期
Translation or Not:no