Glycothermal Synthesis and Characterization of Scheelite-Type NaEuW[sub 2]O[sub 8] Nanophosphors

Abstract

Scheelite-type NaEuW2normalO8 (NEW) nanophosphors were synthesized from a tungsten source and acetates of sodium and europium(III) in 1,4-butylene glycol by a glycothermal reaction. When dodecatungstophosphoric acid hexahydrate (DPA) was chosen as a tungsten source, a glycothermal reaction at temperatures ranging from 200 to 300°C produced crystalline NEW nanophosphors in a single phase. The tetrahedral PO4 unit derived from DPA plays a significant role in the formation of crystalline NEW. The photoluminescence intensity due to the 4f–4f transitions of Eu3+ for the sample prepared at 200°C was over 80 times higher than that of the sample prepared at 300°C . The amount of organic species, determined by thermogravimetry, for the former was three times larger than that of the latter. We therefore conclude that the effect of surface passivation predominantly enhances the photoluminescence intensity of the scheelite-type NEW nanophosphor.

Combustion synthesis and luminescence properties of NaY1−xEux(WO4)2 phosphors

“…Fig. 2 shows the excitation spectra (l em ¼617 nm) and the emission spectra (l ex ¼394 nm) of the NaY 1 À x Eu x (WO 4 ) 2 (x ¼0.1, 0.5 and 1) phosphors synthesized by combustion method at 1100 1C for 2 h. The excitation lines of different samples consist of the broad excitation band at 200-300 nm related to the O-W charge transfer transition and the characteristic excitation lines of Eu 3 þ ascribed to f-f transitions within 4f 6 , which are 7 F 0 -5 D 2 , 5 D 3 , 5 L 6 , 5 G 2 , 5 D 4 and 7 F 1 -5 D 1 , respectively, [14], as shown in Fig. 2(a, c and e).…”

Controlled synthesis and luminescence properties of NaLnW2O8 nanocrystals

“…For a long period, the investigations on the ABM 2 O 8 compounds have been focused on the single crystals as solid-state laser hosts and their optoelectronics applications [12][13][14][15][16][17][18][19]. In recent years, the controllable synthesis and luminescence properties of lanthanide-doped ABM 2 O 8 micro/nanocrystals have also attracted increasing attention [21][22][23][24][25][26]. For example, Fan et al synthesized NaY(WO 4 ) 2 :Eu 2+ and NaY(WO 4 ) 2 :Yb 3+ /Er 3+ nanoparticles by a hydrothermal method and investigated their optical properties [24].…”

“…For example, Fan et al synthesized NaY(WO 4 ) 2 :Eu 2+ and NaY(WO 4 ) 2 :Yb 3+ /Er 3+ nanoparticles by a hydrothermal method and investigated their optical properties [24]. Kasuya [25,26]. However, there have been no reports on NaY(WO 4 ) 2 :Yb 3+ /Tm 3+ nanocrystals to date.…”