Photoluminescence and energy transfer of phosphor series Ba2-zSrzCaMo1-yWyO6:Eu,Li for white light UVLED applications

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

“…However, the main emission was concentrated at 595 nm, which does not give the optimal red colour purity for phosphor converted WLEDs. Substituting Sr for Ba results in lowering of the perovskite lattice symmetry, while substituting W for Mo broadens and shifts the CT band [17]. Thus playing with the composition could allow for optimisation of the optical properties.…”

“…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.…”

“…M6(W,Mo)O12:Eu 3+ (M = Y, Gd, Lu) and AB(W,Mo)O6:Eu 3+ (A = Ca, Sr, Ba; B = Mg, Ca) crystallize in structures with MoO6 groups, where the NUV excitation is enhanced via energy transfer from the host material. The most common synthesis route for these materials is solid state reaction [3,[11][12][13]17,10,19], mainly because of the simplicity of the method, such as no need for soluble precursors or advanced equipment. However, several grindings and re-firings are often necessary to achieve phase purity, and the process readily introduces impurities and defects which would reduce luminous efficacy [20].…”

Octoxy capped Si nanoparticles synthesized by homogeneous reduction of SiCl4with crown ether alkalide

“…Substituting Sr for Ba results in lowering of the perovskite lattice symmetry, while substituting W for Mo broadens and shifts the CT band. 17 Thus playing with the composition could allow for optimisation of the optical properties. The modified Pechini synthesis route developed in this work would be ideal for such a task since it allows strict control of the stoichiometry, homogeneity and phase purity.…”

“…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 noncentrosymmetric lattice sites. M6(W,Mo)O12:Eu 3+ (M = Y, Gd, Lu) and AB(W,Mo)O6:Eu 3+ (A = Ca, Sr, Ba; B = Mg, Ca) crystallize in structures with MoO6 groups, where the NUV excitation is enhanced via energy transfer from the host material.…”