GdBO3: Eu vaterite type particles with fine size, plate morphology, and non-aggregation were first prepared by the mild hydrothermal method. Their characteristics were investigated and compared with those of particles prepared by solid state reactions. The result showed that the hydrothermal method appears to be applicable to prepare high quality phosphors for practical uses. This conclusion was reinforced by the existence of an important improvement in the photoluminescent performances.

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.

以（NH4）2CO3为沉淀剂采用化学共沉淀法在1350℃成功合成了单相Ba1-x Eu xMgAl10O17（0.02≤x≤0.14）蓝色荧光粉。合成温度比传统的高温固相法降低了约250℃。制备的荧光粉颗粒呈准球状形貌，分布均匀且无烧结，晶粒尺寸在0.3μm左右。在254nm紫外光激发下，发射光谱的最大峰值在450nm附近，发射强度比高温固相法提高了大约15%。当x=0.10时发射强度最高。

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.

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.