| 摘要: | 本論文使用中溫水熱法合成以 1,4-cyclohexanedicarboxylate (CHDC)作為配位基含有不同比例稀土元素之 R2(CHDC)3晶體(R= Y, Eu, Tb)及以高溫高壓水熱法合成一系列矽酸鹽晶體 Cs3EuxNd1-xSi6O15 (x= 1, 0.975,0.96, 0.95)，這些晶體皆以粉末 X 光繞射分析圖譜確認晶體為相同結構與純度，以單晶X光繞射分析鑑定其晶體資料，再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。此類晶體均有可見光區的發光外，亦具有奇特之能量轉移現象。我們測量了這些晶體的放光光譜、激發光譜及其發光中心的放光衰退曲線以釐清其能量轉移機制。藉由分析這些光譜學資料，我們證明在R2(CHDC)3晶體中 Tb3+會單向性地轉移能量給 Eu3+，同時在 R2(CHDC)3 晶體中也明顯地發現濃度淬熄(concentration quenching)效應。而在Cs3EuxNd1-xSi6O15 (x= 1, 0.975, 0.96, 0.95)中發現 Eu3+之放光強度與放光衰退曲線在混入Nd3+會有類似鍺酸鹽晶體 K3(EuxNd1-x)3Ge6O18 中 Eu3+之淬熄行為，但其影響幅度矽酸鹽晶體明顯小於鍺酸鹽晶體，我們並證明矽酸基及鍺酸基作為配位基對 Eu3+放光中心有能量轉移的效應。
Mid-temperature and high-temperature hydrothermal synthesis techniques have been used to respectively synthesize R2(CHDC)3, (R= Y, Eu, Tb, and CHDC= 1,4-cyclohexanedicarboxylate) with various compositions of rare earth elements and Cs3EuxNd1-xSi6O15 (x= 1, 0.975, 0.96, and 0.95). Power X-ray diffraction (PXRD) data of these compounds have been obtained for confirming their structure and purity, while single-crystal X-ray (XRD) data were taken for determining accurate crystallographic data. The compositions of rare earth elements were verified by the inductively coupled plasma atomic emission spectroscopy (ICP-AES). We have measured the photoluminescence (PL)spectra, excitation spectra, and emission decay curves of these compounds. In R2(CHDC)3, the energy transfer from Tb3+ to Eu3+ was found to be unidirectional and efficient, whereas the concentration quenching phenomena were also clearly observed in these compounds. The PL quenching caused by mixing Nd3+ in Cs3EuxNd1-xSi6O15 compounds was found to be similar to that in K3(EuxNd1-x)3Ge6O18 compounds with a profoundly smaller quenching magnitude. In these silicates and germanates, the energy transfer between the ligand to the luminescent center was also observed. |
