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Abstract: LiCaBO3 was synthesized by high-temperature solid-state reaction. The influence of different rare earth dopants, i.e. Dy3+, Tb3+, Tm3+ and Ce3+, on thermoluminescence (TL) of LiCaBO3 phosphor was discussed. We studied the TL properties and some dosimetric characteristics of Ce3+-activated LiCaBO3 phosphor in detail. The effect of the concentration of Ce3+ on TL was investigated, the result of which showed that the optimum Ce3+ concentration was 1mol%. The TL kinetic parameters of LiCaBO3:0.01Ce3+ were studied by computer glow curve deconvolution (CGCD) method. The three-dimensional (3D) TL emission spectra were also studied, peaking at 431 and 474nm due to the characteristic transition of Ce3+. We also studied the linearity, annealing condition, reproducibility, fading and different heating rate of the LiCaBO3:0.01Ce3+ phosphor. [Copyright &y& Elsevier]

Abstract: A series of KGd1−x Eu x F4 (x=1, 5, 10, 15, 20, 40, 60, 80 and 100mol%) nanophosphors were prepared by a simple and reproducible hydrothermal route. The structural and morphological properties of the samples were studied by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM), showing uniform nano-sized particles with cubic phase. The excitation spectra disclosed the intrinsic absorption bands of Eu3+ 5L6 state at 393nm and of Gd3+ 6I J state at 272.4nm. From the downconversion (DC) emission spectra, it was found that the optimal Eu3+ concentration was 20mol% and 15mol% under 393nm and 272.4nm excitation, respectively. The nonradiative energy transfer (ET) mechanism is discussed and it turns out that ET of Eu3+–Eu3+ couple and Gd3+–Eu3+ couple occurs mainly via electric dipole–dipole and electric dipole–quadrupole interactions, respectively. From luminescence decay curves, the lifetimes of KGd1−x Eu x F4 nanophosphors are seen to decrease with the increase of Eu3+ concentration. Both the emission spectra and luminescence decay curves show that downconversion ET between Gd3+ and Eu3+ ions is more efficient than that between Eu3+ and Eu3+ ions, thus suggesting potential applications in mercury-free fluorescence lamp and plasma display panel under vacuum ultraviolet (VUV) radiation. [Copyright &y& Elsevier]