The broad bands at around 155nm for GdAl3(BO3)4:Eu, at 184nm for Ca4GdO(BO3)3:Eu, at 183nm for Gd2SiO5:Eu, and at 170nm for GdAlO3:Eu were observed. These bands were assigned to the charge-transfer (CT) transition of Gd3+-O2-. In the excitation spectrumof (Gd,Y)BO3:Eu, a broadened excitation band was observed in VUV region. It could be considered that this band was composed of two bands at about 160 and 166nm. The preceding band was assigned to the BO3 group absorption. The later one at about 166nm could be assigned to the CT transition of Gd3+-O2-, according to the result of GdAl3(BO3)4:Eu, Ca4GdO(BO3)3:Eu, Gd2SiO5:Eu, and GdAlO3:Eu. The excitation spectra overlapped between the CT transition of Gd3+- O2- and BO3 groups absorption. It caused the emission of Eu3+ to take place effectively in the trivalent europium-doped (Gd, Y)BO3 host lattice under 147-nm excitation.

用水热法在低于300℃成功地制备出具有不同形貌的YBO3：Eu3+荧光粉，其反应温度比固相反应降低了约800℃。研究了初始原料、pH值、反应温度、反应溶剂和催化剂等条件对目的产物形貌及粒度的影响。得到了具有Vaterite结构、粒度分布均匀的球形荧光粉的最佳合成工艺。在254 rim激发下，水热法制备的球形Y Euo-o BO3荧光粉最强发射峰位于598rim处，属于Eu抖的 D。一的跃迁，是固相反应所得样品的1.5倍。这些结果表明，在PDP和荧光灯等显示和照明用荧光粉的制备中水热法具有潜在的应用前景。

Single phase europium-activated gadolinium aluminum borate, Gd1-xEuxAl3(BO3)4 (0<x<1) was obtained by the evaporation of its nitrate solution, and calcination at 900 to 1100C in air. All the solid solution was identified as the isomorphs of huntite. Eu31 activated GdAl3(BO3)4 showed intense red emission with CIE chromaticity coordinates of (0.645, 0.330) under 147nm excitation. According to the excitation and emission spectra, the red emission of Eu31 was decreased under excitation of the vacuum ultraviolet (VUV) region (158-160nm), and increased under excitation UV region (258-260nm) with the increase of Eu31 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 274nm peak, corresponding to the 8S72→6I2/11 transition of Gd31 in addition to the f-f transitions of Eu31 were observed. Consequently, the emission of Eu31 was induced by the energy transfer of VUV excitation to the activator Eu31 ions via the co-activator Gd31 in GdAl3(BO3)4.

Vaterite-type GdBO3:Eu3+ phosphor was first prepared by using a mild hydrothermal method. GdBO3:Eu3+ phosphor was fairly controlled as high purity, homogeneous, stoichiometric, uniform plate morphology and nonaggregation powders. The typical powders were plate shaped and 1.6-2.0mm in size. As the synthesis temperature was below 300 C, the recovered phosphor had never been subjected to the phase transition to the calcite type during the chemical reaction. The phosphor showed the excitation band peaked at about 239nm, and the emission band peaked at about 591nm had twice the intensity compared with the conventional phosphor. The excitation and emission peaks were somewhat shifted to shorter wavelength. The GdBO3:Eu3+ phosphor showed maximum intensity in emission for the doped 20 at.% of Eu3+ upon 239nm excitation and 10at.% Eu3+ under 146nm excitation, respectively. Therefore, the energy relaxation pathway to the Eu3+ sites should be different. Also, the partial substitution of Y3+ for Gd3+ was very convenient to improve the emission intensity of Eu3+ under 146nm excitation, whereas the emission intensity was decreased with increasing Y3+ concentration under 239nm excitation.

A broad excitation band in an excitation spectrum of (Gd,Y) BO3:Eu was observed in the VUV region. It could be considered that this band was composed of two bands at about 160 and 166nm. The preceding band was assigned to the BO3 group absorption. The later one at about 166nm could be assigned to the charge transfer (CT) transition of Gd3+-O2. Such an assignment was deduced from the result that broadbands at around 170nm for GdAlO3:Eu, and at 183nm for Gd2SiO5:Eu are due to the CTtransition of Gd3+-O2; this was also identified by CaZr (BO3)2:Eu. Since there are no Gd3+ ions in it; a weak band in the VUV region in the excitation spectrum of Ca0.95ZrEu0.05(BO3)2 was observed. The excitation spectra were overlapped between the CT transition of Gd3+-O2 and BO3 group absorption, and it caused the emission of Eu3+ effectively in the trivalent europium-doped (Gd, Y)BO3 host lattice under 147nm excitation. Intense broad excitation bands were observed at about 155nm for YBO3:Eu and at about 153nm for YAlO3:Eu; it could be attributed to the CTtransition between Y3+ and O2. As a result, under the xenon discharge (147nm) excitation, the intense emission of Eu3+ in GdBO3 was found to be more convenient just because of the partial substitution of Y3+ for Gd3+.