Single phase europium-activated gadolinium aluminum borate, Gd1-xEuxA3(BO3)4 (0 ≤ x ≤ 1) was obtained by the evaporation of its nitrate solution, and calcination at 900 to 1100°C in air. All the solid solution was identified as the isomorphs of huntite. Eu3- activated GdAl3(BO3)4 showed intense red emission with CIE chromaticity coordinates of (0.645, 0.330) under 147 nm excitation. According to the excitation and emission spectra, the red emission of Eu3 was decreased under excitation of the vacuum ultraviolet (VUV) region (158-160 nm), and increased under excitation UV region (258-260 nm) with the increase of Eu3- concentration. In comparison with the absorption data of borates, the 158 nm excitation peak was assigned to the energy level of BO3 groups. In excitation spectra, the sharp 274 nm peak, corresponding to the 8S72→,6I 2/11 transition of Gd3+ in addition to the f-f transitions of Eu3+ were observed. Consequently, the emission of Eu3+ was induced by the energy transfer of VUV excitation to the activator Eu3+ ions via the co-activator Gd3+ in GdAl3(BO3)4.
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