American Chemical Society
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Synthesis, Structure, and Thermally Stable Luminescence of Eu2+-Doped Ba2Ln(BO3)2Cl (Ln = Y, Gd and Lu) Host Compounds

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journal contribution
posted on 2011-10-17, 00:00 authored by Zhiguo Xia, Xiaoming Wang, Yingxia Wang, Libing Liao, Xiping Jing
A new family of chloroborate compounds, which was investigated from the viewpoint of rare earth ion activated phosphor materials, have been synthesized by a conventional high temperature solid-state reaction. The crystal structure and thermally stable luminescence of chloroborate phosphors Ba2Ln(BO3)2Cl:Eu2+ (Ln = Y, Gd, and Lu) have been reported in this paper. X-ray diffraction studies verify the successful isomorphic substitution for Ln3+ sites in Ba2Ln(BO3)2Cl by other smaller trivalent rare earth ions, such as Sm, Eu, Tb, Dy, Ho, Er, Tm, and Yb. The detailed structure information for Ba2Ln(BO3)2Cl (Ln = Y, Gd, and Lu) by Rietveld analysis reveals that they all crystallize in a monoclinic P21/m space group. These compounds display interesting and tunable photoluminescence (PL) properties after Eu2+-doping. Ba2Ln(BO3)2Cl:Eu2+ phosphors exhibit bluish-green/greenish-yellow light with peak wavelengths at 526, 548, and 511 nm under 365 UV light excitation for Ba2Y(BO3)2Cl:Eu2+, Ba2Gd(BO3)2Cl:Eu2+, and Ba2Lu(BO3)2Cl:Eu2+, respectively. Furthermore, they possess a high thermal quenching temperature. With the increase of temperature, the emission bands show blue shifts with broadening bandwidths and slightly decreasing emission intensities. It is expected that this series of chloroborate phosphors can be used in white-light UV-LEDs as a good wavelength-conversion phosphor.