980 nm雷射激發下摻雜鉺離子於Gd2Ti2O7粉末之螢光特性研究

A study on luminescence properties of Er3+-doped Gd2Ti2O7 excited by 980 nm laser diode

宋望輔(Wang-Fu Sung)

指導教授 ： 丁初稷

國立中正大學/工學院/光機電整合工程研究所/碩士(2013年)

摘要

本論文旨在研究改變不同的摻雜濃度與製程溫度來合成Er3+-doped Gd2Ti2O7粉末，並探討其螢光特性。
我們使用溶膠-凝膠法製備Er3+ (1, 5, 10, 15, 20 mol%)-doped Gd2Ti2O7奈米粉末，由實驗結果可得知其在Er3+ (10 mol%)–doped Gd2Ti2O7 粉末在退火溫度超過800℃後，具有良好的結晶特性，其平均結晶顆粒大小隨著退火溫度的提高 (800~1200 ℃) 而從~70 nm增加到~600 nm。在980 nm紅外線雷射激發下，具有下與上轉換發光特性，其發光峰值分別為408 nm (4H9/2→4I15/2)、490 nm (4F7/2→4I15/2)、547 nm (4S3/2→4I15/2)、660 nm (4F9/2→4I15/2)、1534 nm ( 4I13/2→4I15/2)。
Er3+ 離子摻雜濃度為 (1, 5, 10, 15, 20 mol%) 的Gd2Ti2O7 粉末，其可見光、紅外光螢光生命週期衰減曲線均為單一指數；在低摻雜濃度時較容易發生激發態吸收 (excited-state absorption) 上轉換發光機制並產生綠光，但在高摻雜濃度時能量轉移 (energy-transfer up-conversion)、激發態吸收 (excited-state absorption)、交互緩弛能量轉移 (energy-transfer cross- relaxation) 是相互競爭的，這些上轉換機制較容易產生紅光。

並列摘要

Er3+-doped Gd2Ti2O7 nanocrystals were fabricated by the sol-gel method. While the annealing temperature exceeds 800 °C, amorphous pyrochlore phase Er3+-doped Gd2Ti2O7 transfers to well-crystallized nanocrystals, and the average crystal size increases from ~70 to ~600 nm under 800 to 1200 °C/1 h annealing. The Er3+-doped Gd2Ti2O7 nanocrystals absorbing the 980 nm photons can produce the up-conversion (408, 490, 547, and 660 nm; 2H7/2→4I15/2, 2F7/2→4I15/2, 4S3/2→4I15/2 and 4F9/2→4I15/2, respectively) and Stokes luminescence (1534 nm; 4I13/2→4I15/2).
The visible、IR PL decay curve is single-exponential for Er3+ (1, 5, 10, 15, 20 mol%)-doped Gd2Ti2O7 nanocrystals. The upconversion mechanism shows that at low doping concentration more prone to ESA (excited-state absorption) and produces green emission, but in the high doping concentration ETU (energy-transfer up-conversion) , ESA (excited-state absorption), CR (energy-transfer cross-relaxation) are competing with each other, these upconversion mechanisms more prone to red emission.

並列關鍵字

pyrochlore ； erbium ； Gd2Ti2O7

參考文獻

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