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標題: | 新穎矽酸鹽螢光體之合成與螢光特性分析 Synthesis and Photoluminescence Properties of Novel Silicate Phosphors |
作者: | Che-Yuan Yang 楊哲遠 |
指導教授: | 呂宗昕(Chung-Hsin Lu) |
關鍵字: | 矽酸鹽,螢光體,粉體,固相法, silicate,phosphors,powders,solid-state, |
出版年 : | 2012 |
學位: | 碩士 |
摘要: | 本研究成功利用固相法製備出具備高熱定性的矽酸鈣铽摻雜銪離子 (Ca2Tb8(SiO4)6O2:Eu3+) 新型螢光材料。在238 nm的激發光下,Ca2Tb8(SiO4)6O2在波長488, 545, 587和622 nm的位置產生狹窄的放射峰,這些放射峰為Tb3+之5D4至7FJ = 6, 5, 4, 3電子躍遷所致。添加Eu3+至主體後,於590, 613和652 nm的位置額外產生三支較強之放射峰,分別對應到Eu3+之5D0至7FJ = 1, 2, 3電子躍遷。激發及放射光譜指出,添加Eu3+之粉體具備較佳的放光強度以及較廣的有效激發波段。隨著Eu3+的添加量增加,可觀察到Tb3+的放光強度隨之下降,這是由於Tb3+之5D3至Eu3+之5D0的偶極-偶極能量轉移所致。該粉體可藉由調整Eu3+添加量將粉體放光從綠光調整至紅光。
為了改善Ca2Tb8(SiO4)6O2:Eu3+粉體的缺點,在第二部分將Eu2+添加進Ca2Tb8(SiO4)6O2:Eu3+螢光粉體。和無添加銪離子的Ca2Tb8(SiO4)6O2粉體相比,Ca2Tb8(SiO4)6O2: Eu2+, Eu3+中Tb3+的激發峰波長由238 nm移動至295 nm,強度也增加了30%,這是由於Eu2+ 至Tb3+之能量轉移所致。透過在238至380 nm的範圍內調整激發波長,可將Ca2Tb8(SiO4)6O2: Eu2+, Eu3+粉體的放光在橘光至藍白光的範圍內進行調整,並且可分別在260至290 nm和350至380 nm的激發光區間內將粉體發光顏色調整至純白光。 A new kind of silicate oxyapatite phosphors Ca2Tb8(SiO4)6O2:Eu3+ with high thermal stability were synthesized via the conventional solid-state method. Upon excitation at 238nm, Ca2Tb8(SiO4)6O2 exhibited several sharp peaks at 488, 545, 587, and 622 nm, which were attributed to the 5D4→7FJ = 6, 5, 4, 3 transitions of Tb3+. When Eu3+ was introduced into the host, three additional strong emission lines at 590, 613 and 652 nm emerged due to the 5D0→7FJ = 1, 2, 3 transitions of Eu3+. It was indicated that Eu3+-doped phosphors exhibited better emission intensity and broader efficient excitation range than the undoped Ca2Tb8(SiO4)6O2. On increasing the concentration of Eu3+, a decrease in Tb3+ emission was observed due to the energy transfer from 5D3 level of Tb3+ to 5D0 level of Eu3+ via a dipole-dipole mechanism. The energy transfer efficiencies for Ca2Tb8-xEux(SiO4)6O2 phosphors were regularized from 72% to 87% by adjusting x from 0.02 to 0.08. The emitting color of Ca2Tb8(SiO4)6O2 phosphors can be tuned from green to red by well controlling the concentration of Eu3+. To overcome the draw backs of Ca2Tb8(SiO4)6O2:Eu3+ phosphors, including insufficient excitation wavelength and emitting color, Eu2+ ions were doped into Ca2Tb8(SiO4)6O2:Eu3+ in the second section,. In comparison with the excitation spectra of undoped Ca2Tb8(SiO4)6O2, the excitation band of Ca2Tb8(SiO4)6O2:Eu2+, Eu3+ monitored at Tb3+ emission shifted from 238 to 295 nm, and the excitation intensity increased to 1.3 times owing to the energy transfer from Eu2+ to Tb3+. Upon excitation ranging from 238 to 380 nm, Ca2Tb8(SiO4)6O2:Eu2+, Eu3+ exhibited various emitting colors in the region between orange and blue white. It is indicated that the emission color of this phosphor could be tuned to pure white by well controlling the excitation in not only the range from 260 to 290 nm but also the range from 350 to 380 nm. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/16239 |
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顯示於系所單位: | 化學工程學系 |
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