硫氧化釔與氧化釔螢光材料之製備與特性分析

Preparation and Characterization of Yttrium Oxysulfide and Yttrium Oxide Phosphors

劉福文(Fu-Wen Liu)

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(2007年)

https://doi.org/10.6342/NTU.2007.00045

摘要

硫氧化釔(Y2O2S: Eu3+)為新型平面顯示器應用中相當重要的螢光粉之一。於本論文中硫氧化釔以固相法製備，並改變硫的起始物以及混合不同的助熔劑。並針對粉體之晶格結構、表面型態及螢光特性作詳盡的探討。本研究發展出一新型不需助熔劑即可合成硫氧化釔之製程─凝膠塗佈法(Gel-coating)。由凝膠塗佈法所得先驅物經高溫煅燒後可得為六方晶結構之單相粉體。由該法所得硫氧化釔形態主要為不規則形，其大小約為10微米。當先驅物經不同溫度的煅燒後，粉體將會往不同的方向成長，亦可由X-ray繞射圖譜中觀察出其變化。硫氧化釔所放射的紅色螢光，主要由三價之銪離子價電子經5D0-7F2之能階轉換所造成。本研究亦發現硫氧化釔之螢光強度主要受煅燒溫度及其粉體之成長方向有關。

本研究的第二部份為利用微波水熱法合成氧化釔螢光粉體(Y2O3: Eu3+)。以微波法合成氧化釔的先驅物僅需5分鐘。其所合成之先驅物為非晶相，而經高溫煅燒後即可得結晶性良好的單相氧化釔粉體。以微波法合成之氧化釔先驅物為圓球形粉體。詳細觀察其表面形態可知圓球形粉體由許多奈米粉體組成。當氧化釔經高溫煅燒後，粉體仍能保持圓球形之表面形態。氧化釔所放射出之紅色螢光位於螢光光譜上611 nm處，這是由於三價銪離子之價電子於5D0-7F2之能階轉換所產生。由實驗結果可知：螢光粉體之螢光強度及粉體晶粒皆隨著煅燒溫度的增加而有明顯增強的驅勢。根據以上結論，微波熔熱法可於短時間合成圓球形之螢光粉體。

關鍵字

硫氧化釔 ； 氧化釔 ； 微波溶熱 ； 凝膠塗佈 ； 螢光粉

並列摘要

Europium-ion doped yttrium oxysulfide (Y2O2S: Eu3+) is a promising phosphors for flat panel displays. Y2O2S: Eu3+ phosphors were synthesized via a solid state reaction with different fluxes and sources of sulfur. The crystal structure, surface morphology, and photoluminescent properties were investigated. Y2O2S: Eu3+ phosphors were also prepared via a new facile gel-coating route using thiourea as a source of sulfur without adding fluxes. Y2O2S: Eu3+ phosphors with a pure hexagonal structure were obtained after calcination at elevated temperatures. The morphology of Y2O2S: Eu3+ phosphors was irregular shaped particles with the size of 10 µm. The structural orientations were found to be varied with different calcination temperatures. The varied orientations were evidenced from the intensity ratio of diffraction peaks. The red emission of Y2O2S: Eu3+ phosphors was attributed to the transitions from 5D0 to 7FJ (J = 0, 1, and 2) of Eu3+. The photoluminescent intensity of the Y2O2S: Eu3+ phosphors was found to be a function of calcination temperature and crystallographic orientation.

Europium-ion doped yttrium oxide phosphors were synthesized via a rapid microwave-assisted solvothermal route. The microwave processing time for synthesizing precursors of Y2O3: Eu3+ powders was as short as 5 min. The as-synthesized precipitates exhibited an amorphous phase, and well-crystallized pure phase of Y2O3: Eu3+ powders were formed after further calcination. The morphology of the precipitated powders was spherical, and the spherical
particles were composed of small nanograins. The synthesized powders retained the spherical morphology after heating treatments. An intense red emission at 611 nm was assigned to a 5D0-7F1 transition of Eu3+. Both photoluminescent intensity and crystallite size significantly increased with increasing calcination temperatures. The microwave-assisted solvothermal method could be applied to prepare other spherical phosphors.

並列關鍵字

Yttrium Oxysulfide ； Yttrium Oxide ； microwave solvothermal ； gel-coating ； phosphor

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