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標題: | 藉化學取代調控鹵磷酸鹽螢光粉之活化中心格位分布量 Chemical Control of Site Distribution of Activator in Halophosphate Phosphors |
作者: | Chen-Chen Ni 倪晨晨 |
指導教授: | 劉如熹(Ru-Shi Liu) |
關鍵字: | (Sr,Ba,Eu)5(PO4)3Cl,青色螢光粉,全光譜照明,白光發光二極體, (Sr,Ba,Eu)5(PO4)3Cl,cyan phosphor,full spectrum lighting,white light-emitting diodes, |
出版年 : | 2016 |
學位: | 碩士 |
摘要: | 白光發光二極體具發光效率高、可使用時間長、小巧美觀、熱損失少、用電少等優點。提升白光發光二極體之照明品質使其放射光谱與太陽光相近,進而優化人類視覺感受廣受關注。以紫外光二極體激發藍、綠與紅三色螢光粉可獲高顯色性之各色溫白光,然目前之藍光螢光粉無法覆蓋480 - 520 nm之波段,因而全光譜照明尚未實現。
本研究以獲得放射光譜覆蓋480 - 520 nm青光之寬帶螢光粉進而實現全光譜白光LED照明為目的,將研究目標鎖定於高耐水性可為紫外光激發之藍光螢光粉材料(Sr,Ba,Eu)5(PO4)3Cl, 藉化學取代調控該鹵磷酸鹽螢光粉之活化中心格位分布量使光譜展寬,確定最優配方為Sr3.4Ba1.3Eu0.3(PO4)3Cl,其放射波長位於466nm,半高寬達86 nm。本研究亦藉粉末X光繞射、激發放射光譜、光衰減時間、結構精修、 X光吸收光譜等分析方法掌握其陽離子格位占據變化機制,提出活化中心於不同陽離子格位之能階圖,其於未來該材料之發展極具參考意義。本研究藉助熔劑與水蒸氣處理之製程調控方式提升該材料之亮度與熱穩定性,優化後之螢光粉內部量子效率達0.92,於200℃時之放光仍保持25℃時放光強度之93%。 實際封裝所得之 2900 K 白光發光二極體光譜圖與該色溫下太陽光譜近似,成功填補目前缺失之青光波段,獲全光譜照明,其演色性達 95.7,故極具應用前景。 White light-emitting diodes (WLEDs) possess significant advantage overconventional lamps such as high luminous efficiency, longer life time, more compact features and lower power consumption. The optimization of lighting quality of WLEDs has become the focus of concern towards excellent visual comfort in lighting thus making illumination condition similar to natural daylight. High color rendering white light with different color temperature can be obtained by combining Ultraviolet LEDs and several phosphors. However, blue phosphors remain unable to cover the 480 - 520 nm range, hence, the full spectrum lighting has not been achieved. The objective of this research was to develop a broad band cyan phosphor and realize full spectrum lighting in WLEDs. The (Sr,Ba,Eu)5(PO4)3Cl phosphor was the subject of this investigation by broadening its emission spectrum through the chemical control of the activator's site distribution. The appropriate formula was determined to be Sr3.4Ba1.3Eu0.3(PO4)3Cl which showed emission peak at 466 nm and a full width half maximum of 86 nm. The mechanism of activator's site distribution was also discovered by a series of analytical techniques, including X-ray diffraction (XRD), photoluminescence (PL) measurements, luminescence decay curves and X-ray absorption near edge structure (XANES). The energy level scheme for Eu2+ in different sites revealed in this study will have significant meaning and relevance in the further development of this phosphor. To increase its luminous intensity and enhance its thermal stability, this study also used flux and water steam treatment. The optimized phosphor showed quantum efficiency of 0.92 and 93% luminous intensity at 200℃. The Sr3.4Ba1.3Eu0.3(PO4)3Cl phosphor successfully developed and demonstrated to fill in the important cyan gap in a 2900 K WLED device thereby imparting a fuller spectrum just like daylight and high color rendering index of 95.7. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/50007 |
DOI: | 10.6342/NTU201600465 |
全文授權: | 有償授權 |
顯示於系所單位: | 化學系 |
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