| ZnGa2O4 as a self-activating and novel luminescence materials, has been received much attention from researchers recently. It has excellent chemical and thermal stability and color purity, it is also a good luminescent host, and is widely applied to the vacuum fluorescent display, field emission display devices and plasma panel display. Meanwhile ZnGa2O4 also has excellent luminescent and photocatalytic properties. Thus, we combined with the afterglow and photocatalytic properties of ZnGa2O4 in this paper, and use the analysis of afterglow materials refer to the photocatalytic material, to improve the separation of photo-generated electrons and holes through the introduction of a trap effectively, and discussed the method of improving the photocatalytic performance. The major study context in this paper includes those:We prepared ZnxGa2O3+x (x= 1,0.95,0.9,0.85,0.8) long afterglow phosphor by high temperature solid state method. Among them, ZnGa2O4, Zn0.95Ga2O3.95 and Zn0.9Ga2O3.9 are in good agreement with the standard data of ZnGa2O4. For Zn0.85Ga2O3.85 and Zn0.8Ga2O3.8, extra peaks are appeared in addition to the peaks of ZnGa2O4, which correspond to the phase of β-Ga2O3. The red shift phenomenon in the emission spectrum with the decrease of Zn2+ concentration is observed. Because the ionic radii changed, and it would increase the lattice constant of ZnGa2O4. Decay curves showed appropriate reduction in the content of Zn can improve the afterglow property. The reasons have been analyzed by thermoluminescence curve in detail. Photocatalytic analysis showed appropriate amount of Zn concentration can improve the photocatalytic activity of ZnGa2O4. Because Zn0.85Ga2O3.85 would produce more electron traps in the trap level to capture photo-generated electrons which can improve the photo-generated electrons and holes separation effectively.We also synthesized ZnGa2O4+m%H3BO3 (m=0,10) phosphor via high temperature solid state method. X-ray diffraction analysis (XRD) showed that add a small amount of H3BO3 did not change the crystal structure of ZnGa2O4. From the photoluminescence spectra, it can be seen photoluminescence spectra of two samples are similar. Decay curves indicated that the appropriate amount of H3BO3 can improve ZnGa2O4 afterglow property, and it can be observed about 30min long afterglow by naked eyes. Photocatalytic test showed that photocatalytic activity of ZnGa2O4+10%H3BO3 was weaker than ZnGa2O4. The reason has been combined with the analysis of the structure of the material in detail.And the optical performance of Li0.15Zn0.85Ga2O4 phosphors was analyzed. XRD patterns indicated that Li+ ions entered the crystal lattice and replaced Zn2+ ion sites. Raman spectra showed that the first order Raman modes were attributed to Zn2+ ions in the tetrahedral sites. And the photoluminescence and afterglow spectra showed with doping Li+ ions, the luminescent property of ZnGa2O4 improved. Because the concentration of cation vacancies was increased. Decay curves indicating that doping Li+ ions can improve the performance of afterglow, and thermo luminescence characteristics analysis showed the reason that the concentration of trap was increased. Photocatalytic test indicated that Li0.15Zn0.85Ga2O4 exhibited high photocatalytic activities, because of the introduction of more electronic traps, leading to more photo-generated electrons and holes were trapped, and delaying the recombination of electrons and holes. |
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