適用於紫外光二極體之螢光粉研發與優化

Investigation and Optimization of Phosphors for Ultraviolet Light-emitting Diodes

朱政屹(Cheng-I Chu)

指導教授 ： 劉如熹

國立臺灣大學/理學院/化學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.03180

摘要

白光發光二極體為二十一世紀照明曙光，具高發光效率、耐用性、低汙染、體積小等優點。紫外光二極體激發紅、綠與藍螢光粉形成之白光具高演色性、顏色可調性、隨溫度色偏較少、專利障礙少等優點，其為極具潛力之白光發光二極體裝置。
本研究目的在於研發兩種適用於紫外光二極體所激發之主體螢光粉Ba3Si6O12N2與SrAlO4，其中Ba3Si6O12N2乃首例利用氣壓加壓法與非計量比方式合成此氮氧化合物，其具熱穩定、耐濕性等優點，並探討摻雜銪、鈰與鋱元素之光譜特性及其相對應之能量轉移機制。銪摻雜為綠光(522 nm)且高亮度，並利用後處理、晶種法等方式提升螢光強度30%，鈰摻雜為藍光放光並發現銪與鈰具偶極-偶極能量傳遞，而鋱摻雜利用真空紫外光光譜發現其與主體晶格產生電荷轉移能階，導致5D3→7FJ藍光放光增強。
SrAlO4主體為利用組合式化學方式快速合成與分析之優點與田口式方法設計實驗將實驗所需之次數降低外，並分析其摻雜之銪、鈰、鏑與鋰及硼酸助熔劑對此螢光粉於螢光強度、放射波長、餘暉時間等之影響，各成分之影響效益與實驗結果及過去文獻相符，並成功利用此方法優化螢光強度提升7%與餘暉壽命延長7秒，此為首例成功利用組合式化學與田口式方法設計實驗達螢光粉優化，並已發表於國際期刊”Luminescence”，且為期刊封面之專題論文。
本研究之特色為合成法上與優化方式突破過去之研究，並探討其稀土元素之發光機制、化學性質等。最後將Ba3Si6O12N2:Eu實際封裝成白光發光二極體，形成之白光演色性高達96.2，色溫3683 K屬暖色系白光，極具實際應用價值。

關鍵字

螢光粉 ； 二極體 ； 組合式化學 ； 氮氧化物

並列摘要

White light emitting diodes (WLEDs) are the key lighting devices of the 21st century with high luminous efficiency, durability, low pollution, small size etc. Ultraviolet light-emitting diode pumps red, green and blue phosphors to produce white light which have high color rendering index, color tenability, least color shift with temperature, and fewer barriers from patents. This device has great potential to form white light-emitting diode.
In our research, we develop the phosphors based on Ba3Si6O12N2 and SrAlO4 hosts. Ba3Si6O12N2 were synthesized by gas pressure sintering and nonstoichemirstry. This oxonitridosilicates phosphor has advantages of thermal stability, moisture resistance etc. We characterize energy transfer mechanism and optical properties of Ba3Si6O12N2 doping Eu, Ce or Tb. Ba3Si6O12N2:Eu produce high intensity green light emission (522 nm) and enhanced photoluminescence 30% by seed mediating method and acid solution purification. Ba3Si6O12N2 doped Ce are blue light emission and there is dipole-dipole energy transfer from Ce to Eu. In Ba3Si6O12N2 doped Tb, the vacuum ultraviolet photoluminescence spectrum show charge transfer between Tb and the host which enhance 5D3→7FJ blue light emission.
In SrAl2O4 host co-doped with five factors: Eu2+, Ce3+, Dy3+, Li+ and H3BO3, that is long-lasting luminescence material. We investigate these compounds based on a combinatorial approach in conjunction with the Taguchi method which reduce experiment times and analysis effect of each factor via Taguchi method. The results are conforming to previous studies and physics principle. This study are the first one demonstrates that the utility of the combinatorial approach for evaluating the effect of factors on an objective property and estimating the expected performance under the optimal conditions can be improved by the Taguchi method. These studies were published in “Luminescence” as a cover letter and feature article.
We provide a new method to optimized phosphor via combinatorial approach with Taguchi method, and investigate optical properties and energy transfer mechanism of Ba3Si6O12N2 and SrAlO4 hosts doped activators. Finally UV-LEDs were packaged with Ba3Si6O12N2: Eu and commercial phosphors to produce white light. The white light has high color rendering index (Ra = 96.2) and low color temperature (3683 K). It has a great potential as lighting source.

並列關鍵字

phosphor ； oxonitridosilicates ； combinatorial chemistry

參考文獻

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