TAILIEUCHUNG - 69_10

JOURNAL OF SCIENCE, Hue University, Vol. 69, No. 6, 2011SYNTHESIS OF BaMgAl10O17: Eu2+ BLUE COMBUSTION Manh Son, Ho Van Tuyen, Pham Nguyen Thuy of Sciences, Hue UniversityAbstract. Europium ion doped BaMgAl10O17 blue phosphors have been prepared by ureanitrate solution combustion synthesis at 590 0C for 5 minutes. The experimental results , SEM and photoluminescent spectra showed that the phosphors had hexagonal structure, the average particle size of the powders was about 50 nm and the was a broad band with maximum intensity at the wavelength λmax = 455 nm due from 4f65d1 to the 4f7 electronic configuration of Eu2+ : Eu2+ blue phosphor has been used extensively in manufacturing lights (FL), field emission displays (FED), plasma display panels (PDPs).and liquid crystal displays (LCD) [1, 2]. Emission spectra of BaMgAl10O17: Eu2+.phosphor was a broad band with peak at 455nm due to transition from the 4f65d to the 4f7 ground state of ion Eu2+. There are many synthesis technologies of [3, 4, 5, 6]. Every technology has some advantages. Among them,.combustion synthesis has many remarkable advantages as: low heating temperature,.short reaction time. However, luminescent properties of materials depend greatly on conditions [2, 7]. For BaMgAl10O17: Eu2+ phosphors prepared by urea nitrate solution combustion synthesis, urea plays the role of fuel just as the . Besides, the initiating combustion temperature influences the product. In , the experimental results determine the influence of urea concentration and combustion temperature on luminescent properties and structure : Eu2+ phosphors prepared by urea - nitrate solution combustion prepare BaMgAl10O17: Eu2+ phosphors by urea - nitrate solution , starting materials are the mixture of Ba(NO3)2, Mg(NO3)(NO3) and Eu2O3 oxide. Urea was used to supply fuel and reduce agentEu2O3 oxide has been nitrified by nitric acid. Theoretical equation for formation : Eu2+, assuming complete combustion, may be written as:.95.(1 − x)Ba(NO3)2 + xEu(NO3)3 + Mg(NO3)2 + 10Al(NO3)(1−x)EuxMgAl10O17 + by products.+ (urea) →The aqueous solution containing stoichiometric amounts of nitrate metal was mixed by magnetic stirrer and heated at 60oC for 2 hours to gel. Next, the dried at 80oC to dehydrate and combusted at different temperatures within , the product obtained was BaMgAl10O17: Eu2+ (1% mol) with white powderThe influence of heating temperature and urea concentration on luminescent been investigated that the samples BAM were prepared with changing of urea mole.(nurea) from 30 to 80 times product mole (nBAM), combustion temperature could from 570 oC to 630 and discussionsThe crystallographic phase of phosphor with changed urea concentration at the temperature 590oC was confirmed by X-ray diffraction (XRD), the shown in Fig. 1. XRD pattern indicated that the product didn’t appear to phase with nurea = 30 nBAM. With nurea = 40, 50 and 70 nBAM, a low amount of undesirable phase beside BaMgAl10O17 phase. Material single phase structure with nurea = 60 nBAM : BaMgAl10 O 17. 400 . 300Lin (Cps) 70. . . 60 . (Deg)Fig. 1. X-ray diffraction diagram of the samples with different concentrations of spectra of BAM phosphors with different concentration of showed in Fig. 2. Emission of phosphors with concentrations nurea = 40, 50, 60, a broad band with peak at 455nm that characterized transition of e

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