| Today, in the system of fluorescent lamps and LED with tricolour phosphors, commercial red phosphors are still relatively at a disadvantage in price and optical property when compared to blue and green phosphors. It has an important significance on researching for a cheap red phosphor with excellent luminescent property. Rare earth vanadates luminescent materials are a kind of typical matrix sensitized materials and they attract a lot of attention and have been widely used in the fields of display, lighting, and laser materials due to their excellent properties such as good chemical stability, high crystallinity and quenching temperature. We choose to study the vanadate rare earth luminescent materials which the resource in Panxi region of Sichuan are abundant.In this paper, the Ca2Li2BiV3O12:Eu3+ phosphor was synthesized via the combustion method. The phase composition, the phase transition temperature, micromorphology and fluorescence spectra of samples were respectively characterized by X-ray powder diffraction, thermal analysis, scanning electron microscope, surface energy spectrum and fluorescence spectrophotometer. The results show that:the Ca2Li2BiV3O12:Eu3+ phosphor with an excellent luminescence property can be obtained at 680 ℃ for 1 h, and the optimal CA:(Ca2++Li++Bi3++V5+) is 0.5. The fluorescence spectrum of Ca2Li2BiV3O12:Eu3+ shows that the excitation spectrum is composed of a broad band from 200 nm to 385 nm and a number of sharp small peaks extending from 390 nm to 480 nm. The main peak at 277 nm is attributable to the allowed 1A1â†'1T2 transition of VO43-, and the weak shoulder peak at 325nm is attributed to the 1A1â†'T1 transition of VO43-. However, the peak at 325 nm may also be attributed to the 1Soâ†'1P1 transition of Bi3+ ions. The peak from 330 nm to 385 nm is due to the absorption of Bi3+ ions. The small but narrow peaks are associated with the typical f-f transitions of the Eu3+ ions. The emission spectra are described by the well-known emission lines of the Eu3+ ions. The emission of the electronic dipole 5D0â†'7F2 transition at 612 nm is responsible for the strong red light emission.Further, the impact of Eu3+ ion doping concentration, cosolvent, different alkaline earth metal ions (Mg2+, Sr2+, Ba2+) and rare earth ions RE3+(Sm3+, Gd3+, Y3+) on the phase composition and the luminescence properties of phosphors were studied. The results show that:(1) The more Eu3+ is doped, the higher luminescent intensity can be obtained when Eu3+ concentration is not greater than 15 mol%. (2) NH4Cl can improve the luminous intensity of samples and the phosphor exhibits the highest luminescence intensity when its content is 2 mol%(3) The optimal concentration of Mg2+ or Sr2+ ions is 5 mol%. The luminescent intensity decreases when Eu3+ concentration exceed 5 mol%. The main emission peak position shifts from 612 nm to 619 nm when the concentration of Sr2+ ions is 20 mol%. However,5 mol% Ba2+ ions can reduce the luminous intensity of samples. (4) A small amounts of Y3+ ions can improve the luminous intensity of samples and Sm3+ and Gd3+ ions reduce the luminous intensity of samples. The more Y3+ ions are doped, the higher luminescent intensity can be obtained when Y3+ ions concentration is not greater than 40 mol%.Basing on the ascertained optimal concentration of doping one kind of ion, the influence of the different concentrations of Sr2+ and 40mol% Y3+ ions con-doped on the luminescent properties of (Ca1-xSrx)2Li2Bi0.5iY0.4V3O12:0.09Eu3+ (x=0,0.05,0.1, 0.15,0.2) samples was studied. The more Sr2+ is doped, the higher luminescent intensity can be obtained when Eu3+ concentration is not greater than 10 mol%. In the (Ca0.9Sr0.1)2Li2Bi0.6-xY0.4V3O12:xEu3+(x= 0.03,0.06,0.09,0.12,0.15,0.18,0.21) phosphors, the concentration quenching occurs when the Eu3+ content over 18 mol%. |
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