含三價銪/釤元素之鈾氧鍺酸化合物之發光消激機制研究

陳姿寧(Tzu-ning Chen)

指導教授 ： 張伯琛

國立中央大學/理學院/化學系/碩士(2014年)

摘要

本論文使用高溫固態反應法合成一系列不同莫耳比例之三價銪/釤元素之鈾氧鍺酸化合物K4(UO2)Sm2-xEuxGe4O14 (x = 2, 1.81, 1.51, 1.04, 0)。並將這些化合物之單晶與粉末X-ray繞射圖譜與理論繞射圖譜比對，確定其結構與純度。並以感應耦合電漿原子發射光譜分析儀(ICP-AES)鑑定配位中心的元素比例。根據先前研究顯示化合物K4(UO2)Eu2Ge4O14之發光性質非常強，但即使是相同結構的K4(UO2)Sm2Ge4O14其發光效果卻明顯很弱，因而合成不同比例之化合物K4(UO2)Sm2-xEuxGe4O14，並且進行更詳細之放光光譜、激發光譜與時間解析光譜分析，我們發現在化合物K4(UO2)Sm2-xEuxGe4O14中，三價釤離子(Sm3+)和三價銪離子(Eu3+)之發光機制完全不同，Eu3+可由激發UO22+來敏化(Sensitization)發光，但Sm3+則不行。Sm3+有明顯之濃度淬熄效應，但是Eu3+則無。此外Eu3+會隨含量度下降其發光明顯變弱，且放光生命期也變短許多，因此我們探討了化合物中可能造成Eu3+能量淬熄之機制。

關鍵字

鑭係金屬

並列摘要

The hybrid lanthanide compounds of K4(UO2)Sm2-xEuxGe4O14 (x = 2, 1.81, 1.51, 1.04, and 0) were synthesized by the high-temperature solid-state technique. Single-crystal and powder X-ray diffraction (XRD) data of these compounds were obtained to determine the crystal structure as well as the purity. The compositions of lanthanide elements were verified by the inductively coupled plasma atomic emission spectroscopy (ICP-AES). The previous study has shown that K4(UO2)Eu2Ge4O14 has a bright red luminescence, but K4(UO2)Sm2Ge4O14 has a very weak luminescence. We therefore synthesized different compositions of K4(UO2)Sm2-xEuxGe4O14, and conducted detailed photoluminescence spectroscopy, excitation spectroscopy, and time-resolved spectroscopy experiments. In K4(UO2)Sm2-xEuxGe4O14, Eu3+ and Sm3+ have very different emission mechanisms. The Eu3+ emission can be observed by the UO22+ sensitization, whereas the Sm3+ emission cannot be activated by this method. In these compounds, the concentration quenching was observed in Sm3+, but not in Eu3+. On the contrary, the emission intensity and lifetime decrease dramatically as the composition of Sm3+ increases. Possible quenching mechanisms of Eu3+ were analyzed.

參考文獻

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