Synthesis and luminescence properties of YVO4:Eu ,Bi phosphor with enhanced photoluminescence by Bi doping

YVO4:Eu ,Bi phosphors have been prepared by the high-temperature solid-state (HT) method and the Pechini-type sol–gel (SG) method. Spherical SiO2 particles have been further coated with YVO4:Eu ,Bi phosphor layers by the Pechini-type SG process, and it leads to the formation of core–shell structured SiO2/YVO4:Eu ,Bi phosphors. Therefore, the phase formations, structures, morphologies, and photoluminescence properties of the three types of as-prepared YVO4:Eu ,Bi phosphors were studied in detail. The average diameters for the phosphor particles are 2–4 mm for HT method, 0.1–0.4 mm for SG method, and 0.5 mm for core–shell structured SiO2/YVO4:Eu,Bi particles, respectively. Photoluminescence spectra show that effective energy transfer takes place between Bi and Eu ions in each type of as-prepared YVO4:Eu ,Bi phosphors. Introduction of Bi into YVO4:Eu 3+ leads to the shift of excitation band to the long-wavelength region, thus the emission intensities of D0– F2 electric dipole transition of Eu 3+ at 615 nm upon 365 nm excitation increases sharply, which makes this phosphor a suitable red-emitting materials that can be pumped with nearUV light emitting diodes (LEDs). & 2009 Elsevier Ltd. All rights reserved.