Pure red visible emission via three-photon excitation of colloidal Na3ZrF7：Er nanoparticles using a telecom-band laser  

作　　者：叶帅 王广盛 熊茂珍 宋军 屈军乐 谢维信 

机构地区：[1]Key Lab of Optoelectronic Devices and Systems of Ministry of Education/Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China [2]College of Information Engineering, Shenzhen University, Shenzhen 518060, China

出　　处：《Chinese Optics Letters》2017年第1期100-103,共4页中国光学快报（英文版）

基　　金：supported by the National Basic Research Program of China(No.2015CB352005);the National Natural Science Foundation of China(Nos.61525503,61378091,61405123,and 61405062);the Guangdong Natural Science Foundation Innovation Team(No.2014A030312008);the Shenzhen Basic Research Project(Nos.JCYJ20150324141711561,JCYJ20150930104948169,ZDSYS20140430164957663,and KQCX20140509172719305)

摘　　要：We provide the first demonstration of pure red emission in the visible light region via three-photon excitation in monodisperse N a3 ZrF7：Er nanoparticles （NPs） by using a laser operating in the telecommunication band. NPs of -22 nm in diameter are synthesized at 260℃ by the thermal decomposition method. The experimental results reveal that the Na3ZrF7：Er NPs exhibit pure red emission in the visible region under 1480 nm laser excitation, and the emission intensity is significantly influenced by the Er3＋ ion concentration. The decay times of the 4S3/2 → 4F15/2 and 4F9/2 → 4F15/2 transitions of the Er3＋ ions at 540 and 655 nm, respectively, are reduced by increasing the Er3＋ ion concentration in the Na3ZrF7：Er NPs. The suppressed emission intensity result from the defect-related quenching effect： when trivalent Er3＋ ions replac tetravalent Zr4＋ ions, extra Na＋ ions and F- vacancies are formed to re-balance the charge in the Na3ZrF7 matrix. The emission color of the Na3ZrF7：Er NPs is related to the cross relaxation between Er3＋ ions. These results provide an important step toward more ef- fective biological imaging and photodynamic therapy by minimizing the scattering of the excitation light and increasing the penetration depth.We provide the first demonstration of pure red emission in the visible light region via three-photon excitation in monodisperse N a3 ZrF7：Er nanoparticles （NPs） by using a laser operating in the telecommunication band. NPs of -22 nm in diameter are synthesized at 260℃ by the thermal decomposition method. The experimental results reveal that the Na3ZrF7：Er NPs exhibit pure red emission in the visible region under 1480 nm laser excitation, and the emission intensity is significantly influenced by the Er3＋ ion concentration. The decay times of the 4S3/2 → 4F15/2 and 4F9/2 → 4F15/2 transitions of the Er3＋ ions at 540 and 655 nm, respectively, are reduced by increasing the Er3＋ ion concentration in the Na3ZrF7：Er NPs. The suppressed emission intensity result from the defect-related quenching effect： when trivalent Er3＋ ions replac tetravalent Zr4＋ ions, extra Na＋ ions and F- vacancies are formed to re-balance the charge in the Na3ZrF7 matrix. The emission color of the Na3ZrF7：Er NPs is related to the cross relaxation between Er3＋ ions. These results provide an important step toward more ef- fective biological imaging and photodynamic therapy by minimizing the scattering of the excitation light and increasing the penetration depth.

关 键 词：Decomposition Ions Laser excitation Light NANOPARTICLES Photodynamic therapy PHOTONS 

分 类 号：O572.31[理学—粒子物理与原子核物理]