| In recent ten years, exploring new long-lasting phosphorescence material and developing novel effective phosphor powder synthesis method become the focus of optic study. This thesis launches the exploring and researching from these two respects:1. This thesis found that undoped HfO2 which was calcined in high temperature (≥800℃) can emit bluish white long afterglow for about 40 minutes (emission peak is 472nm) after it was irradiated by 254nm UV lamp for 10 minutes. The anion vacancy (F+ center) was produced in the crystal lattice of HfO2 after it was calcined in high temperature (≥800℃), which is refer to the luminescent mechanism in the thesis. In order to further verifying this luminescence is origin of the anion vacancy (F+ center), using HfO2 as matrix and TiO2 as doping agent, under the condition of nitrogen atmosphere, a long afterglow phosphorescence material with more superior performance of long afterglow was prepared by high temperature solid-state method. This phosphor can also emit bluish white long afterglow for about 1 hour (emission peak is 472nm), and its brightness is much stronger than that of undoped HfO2. These long afterglow luminescent materials were characterized by XRD, excitation and emission spectrum, afterglow emission spectrum, afterglow intensity decay curve and thermoluminescence spectrum in the thesis. The influences of calcining temperature, quantities of doped Ti and calcining atmosphere on the luminescent properties were also studied in the thesis. The optimal experiment condition for preparing HfO2: Ti was confirmed as follows: the calcining temperature is 1250℃, the doping ratio of Ti: HfO2 is 0.005:1 (mole ratio), the atmosphere for calcining is nitrogen. The electron trapping center theory was employed to explain the long afterglow luminescence mechanism of HfO2: Ti and the reason why the long afterglow performance of HfO2: Ti was better than that of undoped HfO2.2. Using Zn2SiO4 as matrix and Dy2O3 as doping agent, a long afterglow luminescent material Zn2SiO4: Dy3+ was prepared by high temperature solid-state method. Its excitation and emission peak lie in 220~300nm and 393nm respectively, and the afterglow can last about 15 minutes. Through the comparison experiment, the optimal experiment condition for preparing Zn2SiO4: Dy3+ was obtained as follows: the calcining temperature is 1200℃, the temperature retention time is 5 hours, the flux is H3BO3 (adding amount of H3BO3 is 3%) and the doping ratio of Dy3+: Zn2SiO4 is 0.02:1 (mole ratio). XRD, excitation and emission spectrum, afterglow emission spectrum, afterglow decay curve and thermoluminescence spectrum were used to characterize Zn2SiO4: Dy3+ in this thesis, and the influences of calcining temperature, adding amount of H3BO3, concentration of doped Dy3+and temperature retention time on the luminescence properties of Zn2SiO4: Dy3+ were also studied. The electron-hole recombination theory was employed to explain the long afterglow luminescence mechanism of this luminescent material in the thesis.3. A red luminophore Zn2SiO4: Eu3+ was successful synthesized by combustion method for the first time in this thesis. The optimal condition for preparing this fluorescence is as follows: burning at 600℃and then calcining at 1100℃for 2 hours. XRD, SEM, UV-Vis absorption spectrum and excitation and emission spectrum were used to characterize Zn2SiO4: Eu3+ in this thesis, the influences of calcining temperature, adding amount of urea and H3BO3 and concentration of doped Dy3+ on the emission intensity (5D0â†'7F2) and chromaticity (5D0â†'7F2/5D0â†'7F1) of Zn2SiO4: Eu3+ were also studied. |
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