Preparation And Optical Property Of Doping Nano Zinc-Gallate Phosphor

With the increasing demand for white light illumination light source, the global energy and environment are facing serious challenge. Compared with other light source, the white LED has stronger competitiveness and broader application market due to its more excellent performance than traditional light source. Recently, the white LED is composed of near ultraviolet or ultraviolet LED chip and red, green, blue phosphors. As a new novel material with spinel structure, ZnGa2O4 exhibits the excellent fluorescence properties. Possessing self-excited blue luminescence properties and special crystal structures, ZnGa2O4 can be used as a good luminescent material matrix. In this study, we chose ZnGa2O4 as a luminescent material matrix, and then ZnGa2O4 nanophosphor doped with Eu3+ were synthesized through microwave trisodium citrate-assistant hydrothermal method and microwave ion-exchange method, respectively. Besides, CDs-doped ZnGa2O4 nanophosphors were firstly prepared by the two methods mentioned above. The optical properties and photocatalytic properties of the prepared phosphors were studied. All of the phosphors synthesized in this study have high luminous efficiency and wide near ultraviolet excitation spectrum. The crystal structure and apparent morphology of phosphors were characterized by XRD and SEM, and the relationship of crystal structure and fluorescent properties was also analyzed. The main researches and results are summarized as following:1) A series of Eu3+ single doped ZnGa2O4, CDs single doped ZnGa2O4 and Eu3+/CDs co-doped ZnGa2O4 phosphors were synthesized by microwave trisodium citrate-assistant hydrothermal method. The results indicate that the optimal doping amount of Eu3+ is 8 mol% and the optimal calcination temperature is 600 ? for Eu3+ doped ZnGa2O4 phosphors. Through the study of fluorescence properties for Eu3+ doped ZnGa2O4 phosphors, the red phosphors in light color and color coordinates are close to commercial red phosphors. What's more, it is cheaper and more stable than commercial red phosphors. For CDs doped ZnGa2O4 phosphors, the doping of CDs can significantly enhance the blue light emission of ZnGa2O4 phosphors, and the optimal dosage of CDs is 6.5 mol%. It indicates that the location of emission peak gradually shifts to red region with the increasing amount of CDs; The range of excitation spectrum for CDs/Eu3+co-doped ZnGa2O4 phosphors is 250-450 nm which belongs to the near ultraviolet area and ultraviolet area broadband excitation. Furthermore, the tuneable color emission of CDs/Eu3+ co-doped ZnGa2O4 phosphors from blue to the white light region, and then to red was obtained through adjusting the ratio of Eu3+ to CDs. Through the analysis of crystal structure and fluorescence characteristics of phosphors, we expound the emission mechanism of CDs sensitizating Eu3+ion. Therefore, the phosphor can be a promising single phased phosphor candidate in light emitting diodes.2) CDs doped ZnGa2O4 phosphors were synthesized by microwave ion-exchange method. Their optical property and photocatalytic property were studied. The position of emission peak of CDs doped ZnGa2O4 phosphors is located at 540 nm in green region. CDs/ZnGa2O4 phosphors exhibit excellent persistent luminescence property, and the long-lasting luminescence time is above 30 min. Besides, we find that the doping of CDs into ZnGa2O4 phosphor can enhance the photocatalytic activity of ZnGa2O4 in the experiment of photocatalytic degradation of methyl orange (MO). The degradation results show that ZnGa2O4 phosphor get the highest photocatalytic activity when the doping amount of CDs is 6.5 mol%.