| In the past decade, rare earth ions doped luminescent glass and glass ceramics have been widely researched due to their applications in the filed of solid state laser, optical sensor, scintillation detector, upconversion luminescence, solar cells and white lighting etc. We successfully prepared the glass ceramics of contain BaLuFs nanocrystals by conventional melt quench technical and systematically studied the up-conversion process of Er3+in BaLuF5nanocrystals. Also we prepared Cu+/Sm3+co-doped sodium silicate glass, by adjusting the concentration of Cu+and Sm3+in this system, perfect white light can be obtained finally. These results show that BaLuF5:Er3+transparent oxide fluoride glass ceramic is a promising upconversion material and Cu+/Sm3+codoped sodium silicate glass could find its application in white LED.The main work content as follows:1. Er3+doped BaLuFs nanocrystals transparent glass ceramics:Erbium-doped silicate glasses were successfully prepared by traditional melt-quenching method, named as precursor glass (PG), Afterward, through appropriate crystallization by further heat treatment, transparent glass luminescence properties were systematically investigated by X-ray diffraction (XRD), high-resolution transmission electron microscope (TEM), absorption spectrum, excitation and emission spectra and fluorescence decay curve. XRD and TEM results showed that the single phase BaLuFs nanocrystals were obtained successfully with a narrow size distribution of about20nm in diameter, are evenly distributed in the glass network. Under980nm LD pump, efficient up-conversion luminescence is observed. The green and red emissions of glass ceramics approximately enhanced6500and3000times respectively compared to that of PG. As glass ceramics showed a very strong up-conversion luminescence and obvious Stark splitting, which suggests the incorporation of Er3+into BaLuFs nanocrystals and efficient energy transfer between Er3+ions.In addition, this thesis discusses the treatment temperature influence on the properties of up-conversion emissions, through lifetime decay curves measurement with different heat treatment temperature, we found that with the increase of heat treatment temperatiure, fluorence lifetime of Er3+become longer, this is because more Er3+ions are enriched into the BaLuF5nanocrystals with elevating heat treatment temperature. The above results show that the Er3+doped BaLuFs glass ceramics have potential application in up-conversion detectors.2. Cu+/Sm3+co-doping sodium silicate glass:through melting quenched the preparation of Cu+, Sm3+co-doped sodium silicate glass and its components are73.2SiO2-15.3Na2CO3-6MgO-2ZnO-3.5CaCO3. Through the transmission spectra measurements, we found that the transmittance in the visible range is about85%.With fluorescence spectral characterization of the samples, results show that the luminescence color is adjustable in out glass system. By analyzing the transmission spectra, fluorescent spectra and fluorescent lifetime curve, we also found that there exist an efficient energy transfer in silicate glasses from Cu+to Sm3+. Excited by using the characteristics excitation wavelength of Cu+(λeX=320nm), the luminescence of Cu+and Sm3+can be obtained at the same time. Besides, the luminescence color can be tuned by changing the Sm3+concentration. To obtain perfect white luminescence, Ce3+is co-doped in the glass as a blue light source. When the Ce3+concentration increases to3wt%, perfect white light emission was observed in the CIE Color coordinates (0.320,0.321), very close to the standard white light emission(0.333,0.333). It is concluded that this kind of silicate glass may have potential application in the field of LED lighting,... |
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