Analysis of the Shell Thickness Distribution on NaYF4/NaGdF4 Core/Shell Nanocrystals by EELS and EDS

The structure and chemical composition of the shell distribution on NaYF4/NaGdF4 core/shell nanocrystals have been investigated with scanning transmission electron microscopy (STEM), electron energy loss spectroscopy (EELS), and energy-dispersive X-ray spectroscopy (EDS). The core and shell contrast in the high-angle annular dark-field (HAADF) images combined with the EELS and EDS signals indicate that Gd is indeed on the surface, but for many of the particles, the shell growth was anisotropic.

[1]  Juan Wang,et al.  Direct evidence of a surface quenching effect on size-dependent luminescence of upconversion nanoparticles. , 2010, Angewandte Chemie.

[2]  O. Wolfbeis,et al.  Upconverting luminescent nanoparticles for use in bioconjugation and bioimaging. , 2010, Current opinion in chemical biology.

[3]  Xueyuan Chen,et al.  Upconversion nanoparticles in biological labeling, imaging, and therapy. , 2010, The Analyst.

[4]  J. Boyer,et al.  Remote-control photorelease of caged compounds using near-infrared light and upconverting nanoparticles. , 2010, Angewandte Chemie.

[5]  J. Zuo,et al.  Visualizing materials chemistry at atomic resolution. , 2010, Analytical chemistry.

[6]  C. S. Lim,et al.  Simultaneous phase and size control of upconversion nanocrystals through lanthanide doping , 2010, Nature.

[7]  Taeghwan Hyeon,et al.  Nonblinking and Nonbleaching Upconverting Nanoparticles as an Optical Imaging Nanoprobe and T1 Magnetic Resonance Imaging Contrast Agent , 2009 .

[8]  Hui Guo,et al.  Mesoporous-silica-coated up-conversion fluorescent nanoparticles for photodynamic therapy. , 2009, Small.

[9]  John-Christopher Boyer,et al.  Remote-control photoswitching using NIR light. , 2009, Journal of the American Chemical Society.

[10]  J. Zuo,et al.  Structural characterization of Pt-Pd and Pd-Pt core-shell nanoclusters at atomic resolution. , 2009, Journal of the American Chemical Society.

[11]  Xiaogang Liu,et al.  Recent advances in the chemistry of lanthanide-doped upconversion nanocrystals. , 2009, Chemical Society reviews.

[12]  Zhengquan Li,et al.  An efficient and user-friendly method for the synthesis of hexagonal-phase NaYF4:Yb, Er/Tm nanocrystals with controllable shape and upconversion fluorescence , 2008, Nanotechnology.

[13]  Zhang Yong,et al.  Upconverting nanoparticles as nanotransducers for photodynamic therapy in cancer cells. , 2008, Nanomedicine.

[14]  Kazuo Ishizuka,et al.  Element-selective imaging of atomic columns in a crystal using STEM and EELS , 2007, Nature.

[15]  Jun Lin,et al.  Highly uniform and monodisperse beta-NaYF(4):Ln(3+) (Ln = Eu, Tb, Yb/Er, and Yb/Tm) hexagonal microprism crystals: hydrothermal synthesis and luminescent properties. , 2007, Inorganic chemistry.

[16]  L. Feldman,et al.  Synthesis, Surface Studies, Composition and Structural Characterization of CdSe, Core/Shell, and Biologically Active Nanocrystals. , 2007, Surface science reports.

[17]  Manoj Kumar,et al.  Versatile photosensitizers for photodynamic therapy at infrared excitation. , 2007, Journal of the American Chemical Society.

[18]  Gan-Moog Chow,et al.  Water -soluble NaYF4:Yb,Er (Tm)/NaYF4/Polymer Core/Shell/Shell nanoparticles with significant enhancement of upconversion fluorescence , 2007 .

[19]  Ya-Wen Zhang,et al.  High-quality sodium rare-earth fluoride nanocrystals: controlled synthesis and optical properties. , 2006, Journal of the American Chemical Society.

[20]  R. Prosser,et al.  Water-Soluble GdF3 and GdF3/LaF3 NanoparticlesPhysical Characterization and NMR Relaxation Properties , 2006 .

[21]  T. Krauss,et al.  Shell distribution on colloidal CdSe/ZnS quantum dots. , 2005, Nano letters.

[22]  T. Möller,et al.  Core-level photoemission study of the InAs/CdSe nanocrystalline system , 2004 .

[23]  Horst Weller,et al.  High resolution photoemission study of CdSe and CdSe/ZnS core-shell nanocrystals , 2003 .

[24]  T. Möller,et al.  Investigation of ZnS Passivated InP Nanocrystals by XPS , 2002 .

[25]  M. Botta,et al.  Gd(III)-BASED CONTRAST AGENTS FOR MRI , 2005 .