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Preparation and Characterization of Bi and Eu-codoped Y2O3 Phosphor by Wet Chemical Methods

Author: WangZuoWen
Tutor: ZengRenJie
School: Xiamen University
Course: Materials Physics and Chemistry
Keywords: Microwave hydrothermal method Precipitation method The bismuth Eu co-doped yttrium oxide Phosphor
CLC: TQ422
Type: Master's thesis
Year: 2009
Downloads: 152
Quote: 0
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Abstract


The light-emitting diode (LED) with a small size, less heat, low power consumption, long life, fast response, no mercury pollution, the advantages of flat pack. The excellent performance of the phosphor can effectively improve the luminous efficiency of the LED, bismuth europium-doped yttrium oxide powder of development in recent years, the application potential of the phosphor. Through analysis and comparison of existing synthesis method, precipitation method most likely alternative high-temperature solid-phase the prepared phosphors used in industry. Microwave hydrothermal method to save energy the finer powders can be prepared. Microwave hydrothermal method for the first time studied bismuth europium Preparation and Characterization of Co-doped yttrium oxide phosphor, and this on the basis of a detailed study of the preparation and characterization of the precipitation. Add ammonia to do research using microwave hydrothermal method and oxalic acid precipitating agent preparation of bismuth europium co-doped yttrium oxide phosphor by DTA / TG ??/ DTG, XRD, laser particle size analyzer, SEM, TEM HRTEM, EDS, FTIR and fluorescence spectrophotometer meter, characterization of pH value, the ratio of the precipitating agent, heat treatment temperature, doping and doping ion concentration, the dropwise method and flux preparation conditions on the crystallization process of the phosphor, the particles microscopic morphology and luminescent properties impact. The main findings and progress as follows: precursor prepared by microwave hydrothermal method in 1100 ℃ for 2h (Y 0.94-x , Eu 0.06 , Bi x ) 2 O 3 phosphors. Not doped with bismuth and doping different morphology of the powder particles, (Y, Eu) 2 O 3 rod-shaped, (Y, Eu, Bi) 2 < / sub> O 3 is nearly spherical, this may be the bismuth incorporation suppression (Y, Eu) 2 O 3 crystal (211 ) crystal face growth; bismuth incorporation luminescence enhancement at an excitation wavelength of 346 nm; strength first increased and then decreased with increasing the doping amount of bismuth, and at x = 0.03 to obtain maximum; The system can be used as 320nm ~~ 375nm of near-ultraviolet excitation powder. Fluorescence analysis can be qualitatively to determine some Doping whether the lattice. With oxalic acid plus ammonia precipitation agent is eligible for the precursor; heat treatment after 2h in flake bismuth by europium-doped yttrium oxide of phosphor have been able to observe the crystal at 800 ℃; gradually increases with increasing heat treatment temperature, the powder particle diameter , the crystals gradually improved, the the phosphor luminescence intensity gradually increased, and in 1200 ℃ temperature quenching; different temperature heat treatment the 2h sample the the XRD diagram with JCPDF in 25-1011 (Y, Eu) the 2 O 3 XRD standard pattern comparison, bismuth mixed with a small amount caused by the change of the peak position of the XRD patterns, not observed microwave hydrothermal method. Of doping concentration and bismuth europium-doped yttrium oxide phosphor concentration quenching relationship; anti dropwise with n dropwise little effect on the fluorescence intensity; ultrasonic dispersion dispersed than those without ultrasound precursor particles after the heat treatment than crushing . Join H 3 BO 3 NH 4 F do flux can effectively improve the luminance of the phosphor; but adding H 3 BO 3 the better.

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