Y0.75-xGdxAl0.10BO3：Eu0.10^3＋,0.05R^3＋（R=Sc,Bi）（0.00≤x≤0.45）powder samples are prepared by solid-state reaction and their luminescence properties are investigated. With the replacement of Y^3＋ ions by Sc^3＋ （or Bi^3＋）and Gd^3＋ ions in （Y,Al）BO3：Eu,the intensities of emission at 254 and 147 nm are remarkably improved, because Sc^3＋ inos can absorb UV light and transfer the energy to Eu^3＋ ions efficiently. Moreover, Gd^3＋ and Bi^3＋ ions act as an intermediate ＂bridge＂ between the sensitizer and the activator （Eu^3＋） in energy transfer to produce light in the （Y, Gd）BO3：Bi^3＋, Eu^3＋ system more effectively. After doping an appropriate concentration of Gd^3＋ into Y0.50Gd0.25Al0.10BO3：Eu0.01^3＋,Bi0.05^3＋,the emission intensity reaches its maximum, which is nearly 110% compared with the red commercial phosphor （Y,Gd）BO3：Eu and better chromaticity coordinates （0.650, 0.350） are obtained.
This paper reports that the green phosphor BaAl12O19：0.1Mn^2＋ is prepared by a flux assisted solid state reaction method. The effect of flux systems on the crystal structure, morphology and luminescent properties of the phosphor are studied in detail. The samples are characterized by the application of x-ray diffraction patterns, scanning electron microscopy patterns, luminescent spectra and decay curves. The results show that a pure phase BaAl12O19 can be achieved at the firing temperature above 1300 ℃ by adding the proper flux system, the firing temperature is reduced at least 200℃ in comparison with the conventional solid state reaction method. Maximum photoluminescence emission intensity is observed at 517 nm for （AlF3＋Li2CO3） flux system under vacuum ultraviolet region （147 nm） excitation. The photoluminescence emission intensity and the decay time of these phosphor is found to be more superior to that of the corresponding sample prepared by the conventional solid state reaction method implying the suitability of this route for the preparation of display device worthy phosphor materials.
Homogeneous Zn Se nanocrystals were prepared via surfactant-assisted hydrothermal method.Surfactants agent CTAB was used to control the particle morphology and the growth rate.The structure,morphology and optical properties of Zn Se nanocrystals have been investigated by XRD,TEM and luminescence spectroscopy.The results indicated that the size of Zn Se nanocrystals ranged from 3.0 nm to 5.0 nm with cubic zinc blende structure.Zn Se nanocrystals coated by CTAB were revealed high dispersibility and distribution under TEM.Compared to the bulk Zn Se,the absorption edges and photoluminescence peaks of Zn Se nanocrystals were blue shifted to higher energies due to the quantum confinement effect.The emission intensity was strengthened after coated CTAB compared to bare sample.This was mainly due to the surface passivation.Meanwhile,we simply explored the formation mechanism of Zn Se nanocrystal in hydrothermal system.
