Synthesis and photoluminescence properties of Pb2+ doped Li4CaB2O6

Pure and Pb2+ doped Li4CaB2O6 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 Li4CaB2O6:Pb2+ were observed at 263 and 298 nm, respectively. The dependence of the emission intensity on the Pb2+ concentration for the Li4CaB2O6 were studied in detail. It was observed that the concentration quenching of Pb2+ in Li4CaB2O6 is 0.01 mol. The Stokes shifts of Li4CaB2O6:Pb2+ phosphor was calculated to be 4466 cm(-1). Also, the photoluminescence properties of Pb2+ in various lithium calcium borates (LCB) with different structure was discussed. (C) 2015 Elsevier GmbH. All rights reserved

Synthesis and photoluminescence properties of Dy3+ and Sm3+ doped Li4CaB2O6

Dy3+ and Sm3+ doped Li4CaB2O6 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, Li4CaB2O6: Dy3+ emits 489, 577 and 674nm upon excitation with 345 nm. The second luminescent material, Li4CaB2O6: Sm3+, 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 (Dy3+ and Sm3+) concentration for the Li4CaB2O6 were studied in detail. It was observed that the concentration quenching of Dy3+ and Sm3+ in Li4CaB2O6 are 0.05 and 0.06 mol, respectively. (C) 2016 Elsevier GmbH. All rights reserved

Luminescence concentration quenching of Pb2+ single doped and Pb2+/Dy3+ co-doped strontium tetraborate phosphor

In this study, synthesis and photoluminescence properties of SrB4O7:Pb2+ and SrB4O7:Pb2+, Dy3+ phosphors were investigated. The phases of the synthesized phosphors were determined by X-ray powder diffraction (XRD). Fourier transform infrared (FTIR) analysis confirmed the formation of SrB4O7. The excitation and emission spectra of the synthesized phosphors were analyzed using a spectrofluorometer at room temperature. The dependence of emission intensity on the Pb2+ concentration for Sr1-xPbxB4O7 and Dy3+ concentration for Sr0.985-xPb0.015DyxB4O7 were studied in detail. It was observed that the optimum concentrations of Pb2+ in SrB4O7 and Dy3+ in SrB4O7:Pb2+ are 0.015 and 0.02 mol, respectively. The Stokes shift of SrB4O7: Pb2+ was calculated to be 8500 cm(-1)

Photoluminescence properties and effects of dopant concentration in Bi2ZnB2O7:Tb3+ phosphor

A novel green phosphor, Tb3+ doped Bi2ZnB2O7 was synthesized by conventional solid state reaction method. The phase of synthesized materials was determined using the XRD, DTA/TG and FTIR. The photoluminescence characteristics were investigated using spectrofluorometer at room temperature. Bi2ZnB2O7:Tb3+ phosphors excited by 270 nm and 485 nm wavelengths. The emission spectra were composed of three bands, in which the dominated emission of green luminescence Bi2ZnB2O7:Tb3+ attributed to the transition D-5(4) -> F-7(5) is centered at 546 nm. The dependence of the emission intensity on the Bi2ZnB2O7:Tb3+ concentration for the Bi2-xTbxZnB2O7 (0.01 <= x <= 0.15) was studied and observed that the optimum concentration of Tb3+ in phosphor was 13 mol\% for the highest emission intensity at 546 nm. (C) 2014 Elsevier GmbH. All rights reserved

Luminescence properties of ZnB2O4:Pb2+ phosphors: Suppression of concentration quenching

The UV-A emitting ZnB2O4:Pb2+ crystalline powder phosphors were produced using the conventional solid-state reaction synthesis technique at 830 degrees C for 6 h in air. The morphology and structure of the phosphors were explored by SEM, XRD and FT-IR analyses. The optical properties of the phosphors were examined by UV-vis diffuse reflectance and steady-state photoluminescence (PL) analyses. The excitation and emission bands of Pb2+ doped ZnB2O4 was observed at 304 nm and 388 nm, respectively. The effects of dopant concentration on the PL emission intensities of Zn1-x PbxB2O4 (0 <= x <= 0.15) phosphors were studied. The well-known concentration quenching phenomenon was not observed in the studied range. To explain the observation of suppressed concentration quenching the energy transfer between radiative and non-radiative centers has been discussed. Based on the absorption, excitation and emission results of the samples, a tentative configurational coordinate-energy diagram was proposed. Obtained results show that the ZnB2O4:Pb2+ phosphor is a good candidate for UV-A applications as a rare-earth free wavelength converter