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Dy 3+ and Sm 3+ doped Li 4 CaB 2 O 6 materials were prepared by the solid state reaction. The phase analysis of all phosphors were determined using the X- Ray Powder Diffraction Analysis. The photoluminescence (PL) properties of both phosphors were investigated using spectrofluorometer at room temperature. The first luminescent material, Li 4 CaB 2 O 6 : Dy 3+ emits 489, 577 and 674 nm upon excitation with 345 nm. The second luminescent material, Li 4 CaB 2 O 6 : Sm 3+ , emits (565–570), (602–609), 650 and 712 nm upon excitation with 404 nm. Also, the dependence of the emission intensity on the activator ions (Dy 3+ and Sm 3+ ) concentration for the Li 4 CaB 2 O 6 were studied in detail. It was observed that the concentration quenching of Dy 3+ and Sm 3+ in Li 4 CaB 2 O 6 are 0.05 and 0.06 mol, respectively. [ABSTRACT FROM AUTHOR]

Abstract: Pure and Pb2+ doped M2Mg(BO3)2 (M=Sr, Ba) materials were synthesized at 900°C for 12h in air. The phases of the synthesized materials were determined using the powder XRD. The photoluminescence properties of the synthesized phosphors were investigated using a spectrofluorometer at room temperature. The emission and excitation bands of Sr2Mg(BO3)2: Pb2+ were observed at 330 and 260nm, respectively. And, the emission and excitation bands of Ba2Mg(BO3)2: Pb2+ were observed at 381 and 293nm, respectively. The dependence of the emission intensity on the Pb2+ concentration for the M2−x Pb x Mg(BO3)2 (M=Sr, Ba) was studied in detail. It was observed that the optimum concentrations of Pb2+ in Sr2Mg(BO3)2 and Ba2Mg(BO3)2 are 0.06 and 0.01mol, respectively. The Stokes shifts of Sr2Mg(BO3)2: Pb2+ and Ba2Mg(BO3)2: Pb2+ phosphors were calculated to be 8159 and 7883cm–1, respectively. The luminescence behavior of the Pb2+ ion in M2Mg(BO3)2 (M=Sr, Ba) is discussed. [Copyright &y& Elsevier]

Abstract: Li6CaB3O8.5: M3+ (M3+: Dy and Sm) phosphors were synthesized by a solution combustion synthesis. The synthesized materials were characterized by using the powder XRD. The emission and excitation spectra of these materials were measured at room temperature with a spectrofluorometer. Both Li6CaB3O8.5: Dy3+ and Li6CaB3O8.5: Sm3+ phosphors emit red, yellow and green light. Consequently, these materials are promising phosphors for white LEDs. [Copyright &y& Elsevier]

Pure and Pb 2+ doped Ba 2 Be 2 B 2 O 7 materials were prepared by a solution combustion synthesis method. The phase analysis of all synthesized materials was carried out using the powder XRD. The synthesized phosphors were investigated using spectrofluorometer at room temperature. The excitation and emission bands of Ba 2 Be 2 B 2 O 7 :Pb 2+ were observed at 284 and 396 nm, respectively. The dependence of the emission intensity on the Pb 2+ concentration for the Ba 2 Be 2 B 2 O 7 was studied in detail. It was observed that the concentration quenching of Pb 2+ in Ba 2 Be 2 B 2 O 7 is 0.04 mol. The Stokes shifts of Ba 2 Be 2 B 2 O 7 :Pb 2+ phosphor were calculated to be 9959 cm −1 . [ABSTRACT FROM AUTHOR]

Pure and Pb 2+ doped Li 4 CaB 2 O 6 materials were prepared by the solid state reaction. The phase analysis of all synthesized materials were determined using the powder XRD. The synthesized materials were investigated using spectrofluorometer at room temperature. The excitation and emission bands of Li 4 CaB 2 O 6 :Pb 2+ were observed at 263 and 298 nm, respectively. The dependence of the emission intensity on the Pb 2+ concentration for the Li 4 CaB 2 O 6 were studied in detail. It was observed that the concentration quenching of Pb 2+ in Li 4 CaB 2 O 6 is 0.01 mol. The Stokes shifts of Li 4 CaB 2 O 6 :Pb 2+ phosphor was calculated to be 4466 cm −1 . Also, the photoluminescence properties of Pb 2+ in various lithium calcium borates (LCB) with different structure was discussed. [ABSTRACT FROM AUTHOR]