bromine oxide and up-conversion phosphor white LED with phosphor properties of silicate

Title: bromine oxide and up-conversion phosphor white LED with phosphor properties of silicate
　　Author: Zhang Xinbo
　　Degree-granting units: Zhejiang Normal University
　　Keywords: rare earth luminescent materials;; upconversion;; Gd_3O_4Br: Er ~ (3 +);; GdOBr: Er ~ (3 +);; Sr_2SiO_4: Eu ~ (2 +) phosphors
　　Summary:
　　As the electron shell structure of rare earth ions makes a unique light-emitting rare-earth-doped luminescent materials with other materials do not have many excellent performance. Rare earth luminescent materials with high brightness, long life, no radiation pollution outstanding performance characteristics, has been a hot spot at home and abroad luminescent Neodymium magnets materials. Up-conversion luminescence material in which three-dimensional display, infrared radiation detection, laser anti-counterfeit trade mark has a wide range of application fields. Also with the preparation of white LED technology continues to develop its applications continue to expand, LED with a white phosphor performance and preparation of more and more attention, in particular, is activated by UV excitation of rare earth alkaline earth silicate salt and white phosphor. The subject of this paper is divided into two parts, first part of the bromine oxides of rare earth ion doped upconversion luminescence properties of phosphor research; the other is white LED with Sr2Si04: Eu2-phosphor research.
　　up-conversion luminescence upconversion research and theory.
　　Chapter II with a high-temperature solid-phase synthesis of pure phase orthorhombic Gd3O4Br: Er3 + up-conversion phosphors, X-ray diffraction, field emission scanning electron microscopy, Raman spectroscopy and Fourier transform infrared spectroscopy study of its structural characteristics. The results show that Gd3O4Br low phonon energy, suggesting the Gd3O4Br: Er3 + has a high luminous efficiency. In the 980 nm laser excitation, the observed Er3 +-doped samples Gd3O4Br strong green (514-582 nm) and red (645-692nm) upconversion luminescence. Gd3O4Br: Er3 + (0.1%) samples in the pump power of 1mW (980 nm) laser excitation, the naked eye visible and strong green emission, indicating that this phosphor can be used as conversion phosphor.
　　Chapter by high temperature solid-phase synthesis of pure phase tetragonal GdOBr: Er3 + up-conversion phosphors, X-ray diffraction, Raman spectroscopy and upconversion spectra of its structural characteristics and optical properties. Raman spectroscopy proved that the GdOBr square crystal with low phonon energy, suggesting that the GdOBr: Er3 + upconversion luminescence with high efficiency. At 980 nm and 785 nm laser excitation, were measured GdOBr Er3 +-doped samples strong green (514-582 nm) and weak red (645-692 nm) upconversion luminescence. By upconversion luminescence peak intensity of the pump laser power dependence of the upconversion mechanism, the results show that upconversion luminescence is excited state absorption process. It is noteworthy that GdOBr: Er3 + (1%) samples in the pump power of 1mW (980 nm) laser excitation, the eye is clear that the strong green emission, indicating that GdOBr: Er3 + phosphors are suitable for conversion phosphor.
　　Chapter IV describes the work of white LED with phosphor. Used to restore the atmosphere of heat flux NH4F as solid-state reaction synthesis of a white LED with Sr2SiO4: Eu2 + phosphor, a detailed study of NH4F on Sr2SiO4: Eu2 + phosphor http://www.chinamagnets.biz/Neodymium/Ball-Neodymium-Magnets.php   structure and luminescence properties. XRD results show that adding the right amount of NH4F, at 1100 ℃ high temperature generated Sr2SiO4: Eu2 + as a pure phase monoclinic β-Sr2SiO4. When the adding amount of 6wt% NH4F time, Sr2SiO4: Eu2 + phosphor fluorescent strongest. The emission spectrum composed of two bands, the peak at 474nm and 540nm, respectively, at, down to Sr2SiO4 crystals occupy two different Sr Double column of Eu2 + ions 5d → 4f transition emission. In addition, comparison of different types of flux on Sr2SiO4: Eu2 + luminescence properties of using NH4F as a flux of Sr2SiO4: Eu2 + phosphor fluorescence enhancement is better than NH4Cl and Li2CO3. The results show that use of NH4F as a flux synthesis Sr2SiO4: Eu2 + is a good near ultraviolet chip white LED with a phosphor excitation.
　　Chapter V of this paper summarizes the main work.
　　Degree Year: 2010