藍光與黃光螢光材料之溶膠凝膠法合成與特性分析

Synthesis and characterization of blue-light and yellow-light emitting phosphors via sol-gel method.

陳崇道(Chung-Tao Chen)

指導教授 ： 呂宗昕

國立臺灣大學/工學院/化學工程學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.01614

摘要

本論文研究BaMgAl10O17:Eu2+ (BAM)、Sr3SiO5:Eu2+和Sr2CeO4螢光材料的合成與特性分析。BAM藍光螢光材料以檸檬酸—乙二醇溶膠凝膠法合成。所合成的粉體具有紫外光激發，放射藍光(453 nm)的螢光特性。並探討乙二醇對檸檬酸的比例(φ值)在溶膠凝膠法中對BAM合成的影響，φ值的改變會改變溶膠凝膠反應的機構，發現此變因會改變表面型態與微結構，在1100℃下鍛燒時，BaMgAl10O17結晶相在高φ值下較易生成，所以提高乙二醇對檸檬酸的比例有助於BAM的合成；本論文第二部份是利用檸檬酸—乙二醇溶膠凝膠法合成Sr2CeO4螢光材料，此溶膠凝膠法可以獲得均一晶粒結構和均勻組成的粉體，此溶膠凝膠法可比固相法在較低溫度下合成Sr2CeO4單相，相對於傳統固相法，可獲得較高的光激發光(photoluminescence) 螢光強度，除此之外，也成功獲得陰極激發光(cathodoluminescence)的性質，放射波長主要在藍光區(470 nm)，證實此材料有潛力應用在場發射顯示器之藍光螢光材料上，此外，發現此材料以固相法合成時，超過1000℃，以溶膠凝膠法合成時，超過1200℃會分解而生成SrCeO3造成螢光強度減低；本論文第三部份，研究Sr3SiO5:Eu2+藍光激發螢光材料，利用四乙氧基矽烷為溶膠凝膠法的先驅物合成Sr3SiO5:Eu2+粉體，此粉體激發波長由近紫外光到藍光(460 nm)區域，放射峰主要在黃光區(570 nm)，因此可適用不同的藍光LED晶片，未來可應用為白光LED之螢光轉換材料。

關鍵字

螢光材料 ； BaMgAl10O17 ； Sr2CeO4 ； Sr3SiO5 ； 溶膠凝膠法

並列摘要

This thesis investigated the synthesis and characterization of BaMgAl10O17:Eu2+ (BAM), Sr2CeO4 and Sr3SiO5:Eu2+ phosphors. The blue-light emitting BAM was synthesized via the sol-gel route using citric acid and ethylene glycol. Emission of blue-light (453 nm) was obtained from these phosphors. The luminescent intensity increased as the temperature of heat treatment was increased. The increasing molar ratio of ethylene glycol to citric acid (φ) led to an increase in rate of BAM phase formation at low temperature (1100℃). The variation of φ value resulted in the change of sol-gel reaction mechanism and microstructure of powders. Secondly, Sr2CeO4 was prepared via sol-gel route using citric acid and ethylene glycol. The blue emission (470 nm) was obtained under an excitation of 282 nm. The cathodoluminescent emission (471 nm) under excitation at both low (5 kV) and high (10 kV) acceleration voltage was also observed. Moreover, the sol-gel route resulted in the uniform grain structure and homogeneous composition, which led to enhance luminescent intensity. The significant decrease in the luminescence of Sr2CeO4 was observed when the heating temperature was above 1000℃ for solid state route and 1200℃ for sol-gel route respectively. This decrease is due to the fact that Sr2CeO4 decomposed at high temperature and formed SrCeO3. Finally, Sr3SiO5:Eu2+ phosphor was studied. This material was prepared via the sol-gel route using tetraethyl orthosilicate as precursor. The yellow-light emission at 470 nm was obtained. Sr3SiO5:Eu2+ exhibited a broad excitation band from Near-UV to blue-light region.

並列關鍵字

phosphors ； BaMgAl10O17 ； Sr2CeO4 ； Sr3SiO5 ； Sol-gel

參考文獻

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