新型紫外光發光二極體用碳酸鹽與矽酸鹽螢光材料之製備與特性分析

Preparation and Luminescence Characterizations of New Carbonate and Silicate-based Phosphors for UV-LEDs

張皓雲(Hao-Yun Chang)

指導教授 ： 呂宗欣

國立臺灣大學/工學院/化學工程學研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.01082

摘要

第一部分為新型水菱釔礦螢光粉體之研究，其結構為Y2(CO3)3．nH2O: Eu3+。本研究利用尿素分解之特性，配合水熱法高溫高壓的環境下進行合成反應，成功的合成出水菱釔礦單相螢光粉體。Y2(CO3)3．nH2O: Eu3+螢光粉粉體形狀隨合成溫度之上升而改變，形狀由圓球型成長成棒狀型，粉體粒徑則由1-2μm成長至15-25μm。Y2(CO3)3．nH2O: Eu3+螢光材料之發光特性在254nm波長之激發下，放射波長為615nm，屬於銪離子的5D0 → 7F2之電子躍遷，為一紅色螢光粉。從其發光特性可以說明添加之銪離子佔據結構中釔離子之九配位位置。Y2(CO3)3．nH2O: Eu3+ 在高溫熱處理下，發生熱分解反應並形成Y2O3: Eu3+螢光粉體。得到的Y2O3: Eu3+螢光粉體其型態為棒狀型，在254 nm 激發下，其放射波長為611 nm。

第二部分為新型矽酸鎂釔螢光粉體之研究，其結構為MgY4Si3O13:Ce3+, Tb3+。本研究利用固相法在反應溫度1400oC，N2/H2還原氣氛下煆燒反應4小時，成功合成出單相矽酸鎂釔螢光粉體。只添加Ce3+時，激發波長為330nm，放射波長為480nm，為一藍光螢光粉；只添加Tb3+時，激發波長為240nm，放射波長為544nm，屬於Tb3+之5D4 → 7F5電子躍遷，為一綠光螢光粉。當Ce3+， Tb3+共添加時，經由能量轉移理論，有效的增強螢光材料之發光強度，其能量轉移機制經研究為偶極-四極之交互作用。MgY4Si3O13:Ce3+, Tb3+螢光粉體之CIE色度座標可經由調整Tb3+添加量而位移，研究結果顯示MgY4Si3O13:Ce3+, Tb3+為一有潛力之白光發光二極體用之藍-綠光螢光粉。

關鍵字

螢光粉

並列摘要

A new Eu3+-activated Y2(CO3)3．nH2O phosphor was successfully prepared via the hydrothermal process using urea as a reaction agent. Y2(CO3)3．nH2O: Eu3+ phosphor displayed an intense red emission at 615 nm due to the 5D0 → 7F2 transition of Eu3+ ions under 254 nm excitation. The intensity of this emission significantly increased with a rise in the hydrothermal temperatures. The study of photoluminescence properties demonstrated that Eu3+ ions replaced Y3+ ions in the host lattice at the 9-coordination sites. With increasing heating temperatures, the morphology of Y2(CO3)3．nH2O: Eu3+ powders changed from a spherical to a rod-like shape. Calcination at elevated temperature resulted in thermal decomposition of Y2(CO3)3．nH2O: Eu3+ to form Y2O3: Eu3+. The formed Y2O3: Eu3+ powder exhibited a rod-like morphology with intense red emission.

In the second part of thesis, new phosphors-MgY4Si3O13 codoped with Ce3+ and Tb3+ were prepared. MgY4Si3O13: Ce3+, Tb3+ phosphors exhibited a broad excitation band centered at 330 nm and emission lines of Tb3+ ranging from 450 to 650 nm due to the 5D4 → 7FJ (J = 6, 5, 4, 3) transitions. The energy transfer from Ce3+ to Tb3+ occurred effectively in MgY4Si3O13: Ce3+, Tb3+. The emission intensity of the prepared phosphors was increased significantly due to co-doping Ce3+ ions in the host. The energy transfer form Ce3+ to Tb3+ was demonstrated to be a dipole-quadrupole interaction. The CIE chromaticity coordinates were greatly shifted from blue to green region via changing the concentration of Tb3+. The obtained results revealed that MgY4Si3O13: Ce3+, Tb3+ is a potential blue-green phosphor for white light emitting diodes.

並列關鍵字

phosphors

參考文獻

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