| Nanomaterials show many unique properties for unique quantum size effect, small size effect, surface effect, macroscopic quantum tunneling effect and dielectric confinement effect. These nanomaterials have broad application prospects in the fields of catalysis, medicine, biological marking, communication, and so on. Enhanced luminescence has been reported in rare-earth or transition-metal ions doped oxyfluoride glass ceramics. Unique properties may be obtained if rare-earth or transition-metal ions are doped in 1-D nanostructure materials. With nano science and technology being widely applied in various fields, together with excellent optical properties of rare earth ions doped materials, spectral properties and potential applications of rare-earth ions doped nanoparticles have got more and more attention. This thesis includes three research topics based on the optical properties of rare-earth ions doped nanocrystallines.By doping with rare-earth ions, linearly polarized photoluminescence may be detected from 1-D nanomaterials due to the one-dimensional orientation and confinement effect. And these materials may be used as 1-D light sources, sensing, photoelectric detectors, etc. We preparedβ-NaYF4 nanoparticles with controllable size and shape through simple and non-toxic hydrothermal method. By doping with Tm3+/Yb3+, strong visible luminescence was detected under the excitation of 980nm-LD. The polarized photoluminescence from individual NaYF4 nanorod was characterized, and the polarization ratio was 0.31. Nevertheless, we got different polarization ratios for different emission wavelength at 440nm, 634nm and 703nm. The values were 0.37, 0.27 and 0.97, respectively. However, the understanding of these results from the theoretical aspect is still inadequate and it needs further research. These NaYF4 nanoparticles may be used as 1-D linearly polarized light sources.Glasses.are easy to prepare and make to fibers. High luminescent efficiency can be obtained in fluoride nano-crystallites. Therefore, excellent properties can be expected in rare-earth ions doped oxyfluoride glass ceramics which combine the advantages of glasses and fluoride nano-crystallites. Transparent glass ceramics containing Yb3+/Tm3+-doped CaF2 nano-crystallites were prepared. Their structural and luminescent properties were examined by XRD, HRTEM, SAED, absorption and steady luminescent spectra. Mid-IR luminescent intensities of the glass ceramics were enhanced compared with that of the as-prepared glasses. And the integrated mid-IR emission intensity of Tm3+ in the glass ceramic was increased by two times when YbF3 concentration was 8 mol%. The effect of the temperature on the mid-IR luminescence could almost be ignored. Based on the Judd-Ofelt theory, the J-O parametersΩλ(λ= 2,4,6), spontaneous radiative transition rates, the radiative lifetimes and the fluorescence branching ratios of Tm3+ in both as-prepared glasses and glass ceramics were calculated. Desirable spectroscopic characteristics suggest that these oxyfluoride glass ceramics may be promising laser active medium.Fluorescence intensity ratio technique for temperature sensing has been paid much attention due to high accuracy, low cost, simple detection and insusceptible characteristic to external factors. Strong upconversion intensities should be obtained under low excited pump power. Oxyfluoride glass ceramics are thermostable. And high luminescent efficiency could be obtained from rare-earth ions doped glass ceramics. Temperature-dependent luminescent intensities of Er3+:2H11/2→4I15/2 and 4S3/2→4I15/2 were measured in this paper and the temperature-sensing behavior was demonstrated using fluorescence intensity ratio (R= I522/I543) over the temperature range of 30K-35OK. The sensitivity reached a maximum value of 0.0024/K at 350K. The fluorescence intensity ratio was independent of variations in the excitation intensity. The result reveals that these oxyfluoride glass ceramics may be promising optical temperature sensing materials.
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