Enhancement emission intensity of CaMoO₄ : Eu³⁺, Na⁺phosphor via Bi co-doping and Si substitution for application to white LEDs

Abstract

Through the use of Bi as a co-activator and Si as a substituting element for the host lattice, red emitting , , (x = 0, 0.005, 0.01, 0.05, 0.10, 0.15 and 0.20) and , (y = 0.005, 0.01, 0.02, 0.03, 0.04 and 0.05) phosphors were synthesized by the conventional solid state reaction method, respectively. The photo-luminescent results show all samples can be excited efficiently by UV (396 nm) and blue (467 nm) light and emit red light at 615 nm with line spectra, which are coupled well with the characteristic emission from UVLED and blue LED, respectively. In the Eu3+–Bi3+ co-doped system, both Eu3+ f–f transition and Bi3+ CT transition absorptions are observed in the excitation spectra, the intensities of the main emission line (5D0 → 7F2 transition of Eu3+ at 615 nm) are strengthened because of the energy transition from Bi3+ to Eu3+. The introduction of Si4+ ions did not change the position of the peaks but enhanced the emission intensity of Eu3+ under 396 nm excitations. The results showed that the optimal doping concentration of Bi3+ ions and Si4+ ions was 1 mol%, respectively.

Considerable photoluminescence enhancement of LiEu(MoO4)2 red phosphors via Bi and/or Si doping for white LEDs

“…[28] In this paper, to improve the emission The sharp lines correspond to the characteristic 4f-4f transitions of the Eu 3+ ion within its 4f6 configuration, i.e., the 7 F 0 → 5 D 4 , 7 F 0 → 5 G 4 , 7 F 0 → 5 L 6 , 7 F 0 → 5 D 3 , 7 F 0 → 5 D 2 transitions of the Eu 3+ ion. …”

Synthesis and optical properties of Pr3+-doped LaMgAl11O19–A novel blue converting yellow phosphor for white light emitting diodes

“…The CIE chromaticity coordinates were calculated using a homemade program. The morphology is very important for phosphors as both the dimension and appearance of the grains may affect their luminous efficiency [24]. An SEM micrograph of the LaMgAl 11 O 19 :0.1Pr 3 þ phosphor is shown in Fig.…”

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.…”