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Research on Oxybromide Upconversion Phosphors and Silicate Wled Phosphors

Author: ZhangZuoBo
Tutor: GuoHai
School: Zhejiang Normal University
Course: Condensed Matter Physics
Keywords: Rare earth luminescent materials Upconversion luminescence Gd3O4Br: Er3 GdOBr: Er3 Sr2SiO4: Eu2 phosphor
CLC: O482.31
Type: Master's thesis
Year: 2010
Downloads: 134
Quote: 0
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Abstract


Due to the rare earth ions unique electronic shell structure of rare earth ions doped luminescent materials with other light-emitting materials do not have many excellent properties. Rare earth luminescent materials with high brightness, long life, no radiation pollution excellent performance characteristics, has been the research focus of the light-emitting materials at home and abroad. Upconversion luminescence material widely used in the three-dimensional display, the field of infrared radiation detection, laser anti-counterfeit trademarks. In addition, with the continuous expansion of the white LED preparation technology continues to evolve and its applications, LED white phosphor performance and prepared more and more people's attention, in particular, can be excited by UV light rare earth activated alkaline earth silicate salt white phosphor. In this paper, the main body is divided into two parts, the first part is the conversion luminescence properties of rare earth ions doped bromine oxide phosphor on research; another part of the white LED Sr2Si04: the Eu2-phosphor. The first chapter gives an overview of the upconversion luminescence research progress and upconversion luminescence theory. Chapter II high temperature solid state synthesis of the conversion phosphors the the pure orthorhombic system Gd3O4Br: Er3 by X-ray diffraction, field emission scanning electron microscopy, Raman spectroscopy and Fourier transform infrared spectroscopy to study the structural characteristics. The results show that Gd3O4Br low phonon energy, implied Gd3O4Br: Er3 having a high light emitting efficiency. Er3-doped strong Gd3O4Br sample green (514-582 nm) and red (645-692nm) upconversion luminescence observed in the 980 nm laser excitation. Gd3O4Br: the Er3 (0.1%) sample pump power of 1 mW (980 nm) laser excitation, the naked eye visible green emission, indicating that this phosphor can be used as upconversion phosphors. Chapter synthesized by high temperature solid-phase method the pure tetragonal GdOBr: Er3 conversion phosphor, its structural characteristics and optical properties studied by X-ray diffraction, Raman spectroscopy and upconversion spectra. Raman spectroscopy proved the tetragonal GdOBr has low phonon energy, the implied GdOBr: Er3 has high upconversion luminescence efficiency. Were measured in the 980 nm and 785 nm laser excitation, Er3 doped strong GdOBr sample green (514-582 nm) and weak red (645-692 nm) upconversion luminescence. Upconversion luminescence peak intensity of the pump laser power dependence of the upconversion luminescence mechanism, the results show that the upconversion luminescence excited state absorption process. The noteworthy GdOBr: Er3 (1%) of the sample in the pump power to 1mW (980 nm) laser excitation, the naked eye can obviously see a strong green emission show that GdOBr: the Er3 phosphor is very suitable as a conversion phosphors. The fourth chapter describes the work in white LED phosphor. NH4F flux in a reducing atmosphere high temperature solid state reaction method the synthetic white LED Sr2SiO4: Eu2 phosphor, NH4F detailed study of the structure and luminescence properties of the phosphor Sr2SiO4: Eu2. XRD results show that adding an appropriate amount of NH4F generated in the high temperature of 1100 ℃ of Sr2SiO4: Eu2 pure phase monoclinic system beta-Sr2SiO4. When the addition level of 6 wt% NH4F Sr2SiO4: EU2 phosphor fluorescent strongest. The emission spectrum consists of two bands peaking at 474nm and 540nm at attributed to crystal Sr2SiO4 occupy two different Sr Sites of Eu2 ion 5d → 4f transition emission. In addition, compared the impact of different types of flux on the luminescence properties of Sr2SiO4: Eu2 NH4F as a flux for Sr2SiO4: Eu2 phosphor fluorescent enhance better than NH4Cl and of Li2CO3. The results show that with NH4F as flux synthesis of Sr2SiO4: Eu2 is a good near-ultraviolet chip excited white LED phosphors. Chapter the main work of this thesis are summarized.

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CLC: > Mathematical sciences and chemical > Physics > Solid State Physics > Solid nature of the > Optical Properties > Luminescence
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