White light emitting from YVO4/Y2O3:Eu3+,Bi3+ composite phosphors for UV light-emitting diodes

Abstract

A series of (1−x)YVO4/xY2O3:Eu3+0.006,Bi3+0.006 (0≤x≤0.54) composite phosphors was synthesized in one step by high temperature solid state reaction and the photoluminescence properties were investigated. By means of co-doping Eu3+ and Bi3+ ions into the composite matrices composed of YVO4 and Y2O3 crystals, the YVO4/Y2O3:Eu3+,Bi3+ phosphor exhibits simultaneously the blue (418nm), green (540nm) and orange-red (595, 620nm) emissions. The broad blue and green emissions are attributed to the 3P1–1S0 transitions of Bi3+ ion both in Y2O3 and in YVO4 matrices. Moreover, the sharp orange-red emissions are attributed to the 5D0–7F1,2 transitions of Eu3+ ion in YVO4 matrix. By tuning the mole ratio of YVO4/Y2O3 matrices the white light-emitting could be obtained. The results indicated that when the mole ratio of Y2O3 (x) is at 0.11–0.54mol, the (1−x)YVO4/xY2O3:Eu3+0.006,Bi3+0.006 phosphors emit white light by combining the blue, green and orange-red emissions under the excitation of 360–370nm wavelength which matches the emission of the commercial UV-LED diode. This implies that the phosphors may be the promising white light materials with broad absorption band for white light-emitting diodes.