The concentration dependence of luminescent properties for Eu3+ doped CaWO4 micron spherical phosphors

Abstract

Eu3+ doped CaWO4 micron spherical phosphors with various concentrations were prepared via a precipitation method. The structure and morphology of the samples were characterized by using X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM). The excitation spectra, emission spectra and the curves of fluorescence decay of the samples were measured. The energy transfer type causing Eu3+ concentration quenching between Eu3+ ions was notarized. The critical energy transfer distance (Rc), J–O parameters and the quantum efficiencies of the 5D0 level of Eu3+ were calculated. In addition, the Eu3+ concentration dependencies of photoluminescence properties were studied systematically. The study results indicate that the red emission of Eu3+5D0–7F2 transition (616nm) in the samples can be effectively excited by 394.5nm near-UV light and 465nm blue light and the quenching concentration is high. So the CaWO4:Eu3+ red phosphors may have a potential application for white light emitting diodes.