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

Gd 2 (MoO 4 ) 3 :10%Eu 3+ and AgGdMo 2 O 8 :10%Eu 3+ phosphors were synthesized by a liquid deposition method and characterized by X-ray diffraction, scanning electron microscopy, diffuse reflectance and fluorescent spectrophotometry. Gd 2 (MoO 4 ) 3 phosphor is of orthorhombic structure and AgGdMo 2 O 8 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 Gd 2 (MoO 4 ) 3 :10%Eu 3+ , AgGdMo 2 O 8 :10%Eu 3+ red phosphor has small size and uniform distribution. Therefore, under 395 nm excitation, the emission intensity of AgGdMo 2 O 8 :10%Eu 3+ around 615 nm is twice as much as that of Gd 2 (MoO 4 ) 3 :Eu 3+ . Moreover, the color purity and luminous efficiency of the phosphors converted LEDs based on AgGdMo 2 O 8 :10%Eu 3+ red phosphor and Ga(In)N chips, are also higher than that of Gd 2 (MoO 4 ) 3 :Eu 3+ . The results demonstrated that AgGdMo 2 O 8 :Eu 3+ is more suitable to be a red phosphor applying for white LEDs.