Enhanced photoluminescence of Li3Ba2Gd3 (MoO4)8:Eu3+ red phosphor synthesized by mechanochemically assisted direct solid state reaction method at room temperature

Abstract

For the first time, Li 3 Ba 2 Gd 3-x (MoO 4 ) 8 :x Eu 3? (x = 0.01, 0.03, 0.05, 0.07 and 0.09 mol) red phosphor nanoparticles were prepared using the simple mechanochemically assisted direct solid state reaction method at room temperature and the luminescence effects as a function of Eu 3? ion concentration were studied. The characteristics of the phosphor materials were investigated using X-ray diffraction, Fourier transform infrared spectroscopy, photoluminescence and kinetic decay. For 7 mol% of Eu 3? concentration, the phosphor exhibits a strong excitation peak at 395 nm signifying a strong absorption. The PL emission spectra of Li 3 Ba 2 Gd 3 (MoO 4 ) 8 :0.07 Eu 3? phosphors exhibited an intense peak at 615 nm (red) which relates to 5 D 0 ? 7 F 2 transition of Eu 3? . The most favourable Eu 3? concentration in Li 3 Ba 2 Gd 3 (MoO 4 ) 8 phosphors for intensified red emission results for 7 mol% and above this concentration, the emission intensity falls off as a result of quenching effect. The CIE color coordinates of the Li 3 Ba 2 Gd 3 (MoO 4 ) 8 :0.07 Eu 3? red phosphor coexist very well with the standard values of NTSC. The red emission intensity of the as prepared Li 3 Ba 2 Gd 3 (MoO 4 ) 8 :0.07 Eu 3? red phosphor is 3.2 times better than that of the commercial Y 2 O 2 S:Eu 3? red phosphor prepared by the conventional solid state reaction method.