Luminescent property and application research of red molybdate phosphors for W-LEDs

Abstract

Gd2(MoO4)3:10%Eu3+ and AgGdMo2O8:10%Eu3+ phosphors were synthesized by a liquid deposition method and characterized by X-ray diffraction, scanning electron microscopy, diffuse reflectance and fluorescent spectrophotometry. Gd2(MoO4)3 phosphor is of orthorhombic structure and AgGdMo2O8 phosphor is of tetragonal structure. Both of the phosphors have high absorption and excitation efficiency in near ultraviolet area, which emit mainly at about 615 nm with narrow bands. Comparing with Gd2(MoO4)3:10%Eu3+, AgGdMo2O8:10%Eu3+ red phosphor has small size and uniform distribution. Therefore, under 395 nm excitation, the emission intensity of AgGdMo2O8:10%Eu3+ around 615 nm is twice as much as that of Gd2(MoO4)3:Eu3+. Moreover, the color purity and luminous efficiency of the phosphors converted LEDs based on AgGdMo2O8:10%Eu3+ red phosphor and Ga(In)N chips, are also higher than that of Gd2(MoO4)3:Eu3+. The results demonstrated that AgGdMo2O8:Eu3+ is more suitable to be a red phosphor applying for white LEDs.