白光發光二極體用之具高穩定性螢光粉研究

Investigation of Phosphors with High Stability for White Light Emitting Diodes

柯韋志(Wei-Chih Ke)

指導教授 ： 劉如熹

國立臺灣大學/理學院/化學研究所/碩士(2009年)

https://doi.org/10.6342/NTU.2009.03110

摘要

近年來白光發光二極體(white light emitting diode; WLED)備受全球矚目，其具高效率、壽命長、無熱輻射、無汞汙染、反應速度佳、體積小等優點，為二十一世紀照明之新光源。目前已有多種產生白光之方法，市面上以藍光LED搭配黃色螢光粉產生白光為目前業界中較為成熟之技術，但其專利權幾乎被日系廠占據，且其存在演色性較差、色溫偏高或不均、白光不易控制等缺點。故此法雖為現階段市面主流，但仍具許多改善空間。有鑑於此，UV LED搭配紅、綠、藍色螢光粉除專利權之阻礙較小外，且具低成本、光色均勻不易偏色、高演色性等優點，並可與多種螢光粉搭配，為未來發展之主要趨勢。
本研究將研發適合UV LED激發之高色純度紅、綠、藍(R, G, B)螢光粉，且具高發光效率與高穩定性。研究內容著重於BaMgAl10O17與Ca2Si5N8兩個系列之螢光材料，前者添加Eu2+與Mn2+為發光中心，探討其發光特性與能量轉移機制，並研究助熔劑效應與粉體穩定性之關係；後者則克服一般氮化物之合成困難，於常壓下合成純相之氮化物紅色螢光粉。本研究並將所合成之紅、綠、藍(R, G, B)螢光粉以UV LED激發製作完成白光發光二極體。
於本研究中所使用之分析方法為主要以粉末X光繞射儀(X-ray diffraction; XRD)鑑定樣品之純度及其長程有序晶體結構；利用光激發光光譜儀(photoluminescence; PL)分析螢光粉之激發光譜及放射光譜特性，並將發射光譜以軟體轉換為CIE色度座標；以掃瞄式電子顯微鏡(scanning electron microscope; SEM)進行樣品表面型態分析；並測試粉體之熱穩定性與濕度穩定性，且將粉體封裝後量測其電穩定性。本研究部分成果已申請一件專利，並已完成英文論文撰寫，且投稿於國際期刊中。

關鍵字

螢光粉 ； 白光發光二極體

並列摘要

White light-emitting diode (WLED) are regarded as the next generation light source because of their high efficiency, long lifetimes, lower heat generation, absence of mercury, short response times and many more favorable properties. Many methods are commonly applied to generate white light. The blue LED that coated with yellow phosphor is simpler and more widely used. However, the method faces serious problems of patent issue, poor color retention and high color temperature. Another approach is to use UV LED fitted with three phosphors emitting blue, red and green, this type offers superior color uniformity with a high color rendering index and excellent quality of light.
The aim of this work is to develop the phosphors based on BaMgAl10O17 and Ca2Si5N8 nitride host material, which can produce superior blue, green and red lights under excitation by UV LED. The luminescence properties and energy transfer of BaMgAl10O17:Eu, Mn were investigated. In addition, the influence of the fluxes on the luminescence, moist and thermal stability was examined. Furthermore, Ca2Si5N8:Eu, a nitride phosphor, which is produced by a solid-state reaction under ambient pressure conditions as a red phosphor. We prepared WLED by coating the synthesized blue, green and red phosphors on a UV LED chip to verify the real application capability.
The characterization of the phosphors was carried out by X-ray diffraction (XRD) to study the crystal structure, and photoluminescence (PL) measurements were investigated, and the emission spectra were transformed by the program to realize their CIE color coordination and color purity. We utilized scanning electron microscope (SEM) to research their particle size and morphology. The thermal and moist stability were examined. Some results of this study are applying for one patent and submitting for one publication.

並列關鍵字

phosphor ； white light emitting diodes

參考文獻

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