| Summary: | 碩士 === 義守大學 === 材料科學與工程學系碩士班 === 96 === Abstract
There are not many choices of phosphors which are suitable to use in the low voltage FED. To increase the competitiveness of FED, more phosphors for low voltage should be developed. Furthermore, electrons will easily charge on the surface of insulated phosphors and the degradation of phosphors occurs because electron beam under low voltage cannot lead to the great penetration. Therefore, in this research, new phosphors will be developed and the modification of CRT phosphors would be undertaken. It is believed that both methods are expected to improve the efficiency of CL phosphors in the environment of low voltage.
In this study, the urea hydrolysis method and subsequent hydrothermal method would be employed to synthesize nanosized Y2O3:Eu phosphors with different shapes, and commercial micrograded and self-synthesized nanosized Y2O3:Eu phosphors were further coated with transparent conduct film by sol-gel method in order to enhance electrical conductivity of phosphors. XRD analysis was used to analyze the crystal structure, SEM and TEM were applied to observe microstructure, and finally, the screen printing method was used to fabricate two electrodes CNT–FED components. In addition, the cathodoluminance of phosphors was measured at the voltage ranged from 0V to 1000V.
The results indicated that as the phosphors are pretreated by soaking in the D.I. water, the AZO coating of commercial Y2O3:Eu phosphors is more continual and homogeneous with compared to the one after soaking in IPA. In addition, the concentration of the solvent, kinds of stabilizers, and reaction temperature and coating time affect the thickness and continuity of AZO coating. Moreover, Y2O3:Eu precursors with different structures and shapes can be synthesized by urea hydrolysis method and subsequent hydrothermal method, and the granulous, columnar and platy Y2O3:Eu could be synthesized, after calcinations at 600℃ for 2hrs.
The commercial Y2O3:Eu phosphors with AZO coating exhibit a great result in the measurement of CL brightness. The brightness of AZO–coated commercial phosphor is promoted by promotes a hundred times, and the result shows that the thicker AZO coating is, the better the promotion of brightness is. When the thickness of AZO coating is 30.1±5.3 nm, the brightness under 800V voltage can reach 140.7±7.2 cd/m2. When the thickness of coating is increased to 108.4±23.8 nm, the brightness is 233.0±42.3 cd/m2 under 600V. However, the brightness of commercial phosphors under 800V can only reach 0.19±0.01cd/m2. Without AZO coating, the brightness of phosphors synthesized by 200℃ hydrothermal reaction can reach 112 cd//m2 under 500V low voltage. The brightness of self-synthesized phosphors with AZO coating is promoted apparently.
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