YAG：Tb螢光粉的合成、結構及其螢光特性之研究

綜合前人研究，添加稀土類Tb^(3+)進入釔鋁石榴石（Y_3Al_5O_(12)，YAG）中，能夠改變原本YAG晶格之能階分裂狀態，使能在可見光範圍有螢光之特性。故本研究對YAG主體添加0.1，1.0和10mol％之Tb^(3+)，研究不同添加量對其合成、結構與螢光特性之影響。製程為利用固相反應搭配簡易噴霧乾燥法與後續還原N_2煆燒1600℃／4h來合成球狀螢光粉。從實驗結果DTA得知，固態反應物在合成過程呈現不均勻之擴散反應，且Tb^(3+)添加愈多，θ至α-Al_2O_3相變峰有提前趨勢；由粉末XRD結果可知，愈多的Tb^(3+)，造成愈不易合成純YAG相，且由晶格常數的增加確定活化物進入YAG晶格中。由GSAS軟體分析結果也可得知Tb^(3+)確實取代Y^(3+)；由Raman光譜可知，添加愈多的Tb^(3+)，Tb-O鍵結愈明顯，也確證實了取代的發生；由PL發光光譜得知，添加愈多的Tb^(3+)，其發光特性光譜集中於約475～630 nm，且激發光譜也明顯出現Tb^(3+)之特性光譜。分析^5D_4至^7F_5放光能階之殘光衰變情形，得知愈多的Tb^(3+)其decay time愈短；由CIE色度座標也可知愈多的Tb^(3+)添加，其螢光飽和度與色純度愈高。

關鍵字

噴霧造粒； Tb^(3+)取代；螢光特性

並列摘要

Previous studies concluded that the rare earth Tb^(3+) in host Y_3Al_5O_(12) (YAG) can change the energy state splitting and display fluorescence property. This study focused on synthesis, structure and photoluminescence of YAG:Tb^(3+) phosphors when doped with 0.1, 1.0, or 10 mol% Tb^(3+). The phosphor was produced in solid-state reaction with a simple spray-drying method followed by calcining in a N_2 atmosphere at 1,600℃ for 4 hours. DTA results show that heterogeneous mass diffusion dominates the synthesizing process and that the θ to α-Al_2O_3 exothermic peak showed up earlier for the higher mol% Tb^(3+). The powder XRD data showed that with higher mol% Tb^(3+) the chance of forming pure YAG phase is diminished. But, the increase in cell parameter showed that the activator resides in the YAG cells. Results from GSAS fitting and Raman spectra analyses showed that Tb^(3+) replaced Y^(3+). PL emission spectra analysis results showed that the higher the Tb^(3+) content, the more Tb^(3+) characteristic spectra concentrate in 475~630 nm. The decay time of ^5D_4 to ^7F_5 was shorter with more Tb^(3+) in YAG. According to the CIE coordinate of YAG:Tb phosphor, more Tb^(3+) doped into the host the higher the chroma and hue appeared.

並列關鍵字

Spray-granulating ； Tb^(3+) replacement ； Fluorescence property

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