以溶膠-凝膠法製備MgAl2O4: M(M=Mn, Eu, In )螢光粉之光致發光特性研究

本研究是以界面活性劑及檸檬酸兩種不同之螯合劑，並個別摻雜Mn、Eu及In三種不同活化劑，利用溶膠-凝膠法製備MgAl2O4之螢光粉體，研究摻雜不同濃度及不同煆燒溫度對粉體之特性影響。研究重點包括：材料的成份設計與合成，晶粒形貌、表面形態、晶體結構及發光特性測定等。 XRD結果顯示，經煆燒800℃持溫2小時後合成出MgAl2O4立方尖晶石結構，摻雜Mn和Eu時隨著濃度提高皆無雜相出現，但摻雜In時隨著濃度提高會有In2O3的相出現。SEM結果顯示，使用不同螯合劑會產生不同的粉末形態。TEM結果顯示，利用檸檬酸為螯合劑時，會使晶粒緊密連接在一起，繞射圖比對後確定為MgAl2O4之晶體結構。PL結果顯示，利用F127為螯合劑未摻雜之MgAl2O4，在放射波長407nm條件下，於247nm處有較強之激發峰，此處為主體材料的能帶發光，隨著溫度上升強度明顯下降，利用檸檬酸為螯合劑摻雜Eu之MgAl2O4，在激發波長395nm條件下，有580、593、617、655、705nm等Eu3+離子所造成之放射峰，其中為617nm(5D0→7F2)處之放射峰值最強，而經CIE色度座標圖確認發紅光。

關鍵字

MgAl2O4 ；螢光粉；溶膠-凝膠法；錳摻雜；銪摻雜；銦摻雜

並列摘要

In this study, undoped and doped MgAl2O4 were prepared by sol-gel process with a triblock copolymer F127 and citric acid as chelating agents, and Mn, Eu, and In as activators. The effects of calcining temperature and different doping concentration on the crystal structure, morphology and photoluminescence properties were investigated. XRD analysis showed that MgAl2O4 with cubic spinel structure was obtained. There were no impurities found in Mn-doped and Eu-doped MgAl2O4 with increasing concentration, but In2O3 was appeared in In-doped MgAl2O4 with increasing concentration. SEM results revealed that the samples have different morphology as used different chelating agents. TEM images showed that grains agglomerated with citric acid as chelating agent, and the diffraction pattern also confirmed MgAl2O4 structure. As the chelating is F127, PL results showed the emission peaks located at around 407 nm originate from the host material, and excitation at 247nm. The intensities are decrease gradually with increasing calcination temperature. As the chelating is citric acid, the emission peaks at 580 nm, 593 nm, 617 nm, 655 nm and 705 nm were attributed to the (5D0→7F0) (5D0→7F1), (5D0→7F2), (5D0→7F3) and (5D0→7F4) transitions of Eu3+ ion, and excitation at 395nm. The Commission Internationale de l'Eclairage (CIE) coordinates results showed that the emission color shift can be tuned from bluish to reddish by doped Eu3+ ion.