Photoluminescence and Raman Spectra of Double-Perovskite Sr[sub 2]Ca(Mo/W)O[sub 6] with A- and B-Site Substitutions of Eu[sup 3+]

Abstract

A-and B-site substituted double-perovskite Sr 2 CaMoO 6 by Eu 3+ have been synthesized using solid-state reactions and characterized by X-ray diffraction, Raman spectroscopy, and photoluminescence measurement. Raman spectra are used to identify the Aand B-site substitutions, because specific Raman peaks corresponding to different ions motion are sensitive to each situation. Raman data reveal that both the A-and B-site substituted solid solutions are formed. The photoluminescence intensity of the B-site substituted Sr 2 CaMoO 6 is evidently higher than that of the A-site substituted phosphor. The WO 6 group introduced into Sr 2 CaMoO 6 :Eu 3+ ,Li + acts as an energy obstacle to prevent energy transfer among MoO 6 groups, leading to more energy being trapped by Eu 3+ , and a higher photoluminescence intensity is obtained. The phosphor with optimized composition Sr 2 Ca 0.80 Li 0.10 Eu 0.10 Mo 0.10 W 0.90 O 6 shows a better luminescence intensity than the commercial phosphor Y 2 O 2 S:Eu under 395 nm excitations.

Yb3+ site occupation and host sensitization luminescence of a novel near‐infrared emitting Sr2CaMoO6:Yb3+ phosphor

“…The Rietveld refinement was performed using the TOPAS-Academic program [12] and the P2 1 /n structure model was reported by Prior et al [13], which converged to R wp = 4. (1) and A 1g Raman peaks give rise to a blue-shift for A-and B-site substitutions of Eu 3+ ions in the Sr 2 CaMoO 6 system, respectively [15]. In the present case, as the concentration (x) of Yb 3+ ions increases, for the peaks in the range 100-180 cm -1 (correlated with mode T 2g (1)) no obvious changes can be observed (Fig.…”

Synthesis and photoluminescence properties of color-tunable BaLa2WO7:Eu3+ phosphor

“…According to the data reported for other tungstate phosphors [22][23][24][25], the CTS band of the WO 6 group is located between 250 and 360 nm. However, the CTS band of the oxygen 2p orbital to the empty 4f orbital of Eu 3+ is weak and immersed in the CTS band from the WO 6 group [22][23][24][25]. The sharp peaks between 360 and 600 nm can be attributed to the intra-4f forbidden transitions of Eu 3+ , which is consistent with the UV-vis optical absorption spectrum of BaLa 1.6 Eu 0.4 WO 7 .…”

“…In the excitation spectra, the host absorption band and the charge-transfer band of Eu 3+ -O 2− were not clearly detected, which might be due to a possible overlap of the CT band with that of the tungstate group found in AgGd 0.95 Eu 0.05 (WO 4 ) 2−x (MoO 4 ) x [19]. According to the data reported for other tungstate phosphors [22][23][24][25], the CTS band of the WO 6 group is located between 250 and 360 nm. However, the CTS band of the oxygen 2p orbital to the empty 4f orbital of Eu 3+ is weak and immersed in the CTS band from the WO 6 group [22][23][24][25].…”

Luminescent Eu3+-doped NaLa(WO4)(MoO4) and Ba2CaMoO6 prepared by the modified Pechini method

“…However, the technology is limited by the lack of a stable and efficient red phosphor. A much researched group of novel red phosphor materials are the Eu 3+ doped oxides of Mo and W, including compounds such as Ca(W,Mo)O4:Eu 3+ ,Li + [1,2], M + M 3+ (WO4)2−x(MoO4)x:Eu 3+ (M + = Li, Na, K; M 3+ = La, Gd, Y, Lu, Bi) [3][4][5], M6(W,Mo)O12:Eu 3+ (M = Y, Gd, Lu) [6][7][8][9] and AB(W,Mo)O6:Eu 3+ (A = Ca, Sr, Ba; B = Mg, Ca) [10][11][12][13][14][15][16][17][18]. The first two compounds crystallize in the scheelite structure, where there is enhancement of NUV excitation due to non-centrosymmetric lattice sites.…”