The doping concentration dependent tunable yellow luminescence of Sr5(PO4)2(SiO4):Eu2+

Color tunable yellow-emitting phosphors of Sr5-5xEu5x(PO4)(2)SiO4 (x = 0.05-0.15) were prepared by conventional solid-state reaction method. The X-ray powder diffraction patterns, the photoluminescence excitation and emission spectra were measured. The main excitation bands of the phosphors locate at a broad band extending from 300 to 500 nm, which can match the emission of ultraviolet- and blue-emitting diode chips. The tunable luminescence color was realized by the changing Eu2+ doping in Sr-5(PO4)(2)SiO4. The structure and luminescence properties were investigated. Sr5-5x(PO4)(2)SiO4:Eu-5x displays two typical luminescence centers, which originate from two different Sr2+ (Eu2+) sites in the host. The site-occupation, the luminescence intensity and energy transfer between the Eu2+ ions occupying two different crystallographic Sr2+ sites were discussed on the base of the luminescence spectra and crystal structure. This is helpful to improve this phosphor for a potential application as a white light emitting diode phosphor. (C) 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved.