Upconversion emission enhancement of Gd³⁺ ions induced by surface plasmon field in Au@NaYF₄ nanostructures codoped with Gd³⁺-Yb³⁺-Tm³⁺ ions

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• 作者：Tao Jiang ; Ye Liu ; Shusen Liu ; Ning Liu ; Weiping Qin ; ^{wpqin@jlu.edu.cn}
• 关键词：Luminescence enhancement ; Au nanoparticles ; Gd3+ ions ; Energy transfer
• 刊名：Journal of Colloid and Interface Science
• 出版年：2012
• 期刊代码：125_00219797
• 类别：ch
• 出版时间：1 July, 2012
• 卷：377
• 期：1
• 页码：81-87
• 文件大小：1046 K

摘要

Au nanoparticles (NPs) attached 尾-NaYF₄ nanocrystals codoped with Gd³⁺-Yb³⁺-Tm³⁺ were synthesized by a facial solution method. The UV-vis-near-infrared absorption spectrum shows typical surface plasmon resonance band of Au NPs in addition to the characteristic absorption peaks of Yb³⁺ ion. X-ray diffraction and selected area electron diffraction results indicate the existence of Au NPs. The transmission electron microscopic image reveals the formation of Au@NaYF₄ nanostructures. Enhanced ultraviolet (UV) upconversion luminescence (UCL) was observed in the nanostructures under the excitation of 980-nm infrared laser. The largest enhancement factor was obtained as 76 for the ⁶I_J 鈫?#xA0;⁸S_7/2 emission of Gd³⁺ ions, which was much larger than those emission enhancement factors of Tm³⁺. It is for the first time to our knowledge that the emission enhancement of Gd³⁺ ions was obtained. Local field enhancement induced by Au NPs was found to be responsible for the UCL enhancement, which is the further experimental evidence of local field enhancement theory. Magnetic measurements of the Au@NaYF₄ nanostructure indicated it would have potential application in magnetic resonance imaging.