Controlled Synthesis and Single-Particle Imaging of Bright, Sub-10 nm Lanthanide-Doped Upconverting Nanocrystals
| Autor: | Delia J. Milliron, Emory M. Chan, Bruce E. Cohen, Gang Han, P. James Schuck, Daniel J. Gargas, Elan M. Katz, Alexis D. Ostrowski |
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| Rok vydání: | 2012 |
| Předmět: |
Lanthanide
Time Factors Materials science Doping General Engineering Analytical chemistry General Physics and Astronomy Nanoparticle Lanthanoid Series Elements Photobleaching Molecular Imaging Nanocrystal Luminescent Measurements Nanoparticles Nanotechnology General Materials Science Particle Size Luminescence Phosphorescence Biological imaging |
| Zdroj: | ACS Nano. 6:2686-2692 |
| ISSN: | 1936-086X 1936-0851 |
| DOI: | 10.1021/nn3000737 |
| Popis: | Phosphorescent nanocrystals that upconvert near-infrared light to emit at higher energies in the visible have shown promise as photostable, nonblinking, and background-free probes for biological imaging. However, synthetic control over upconverting nanocrystal size has been difficult, particularly for the brightest system, Yb(3+)- and Er(3+)-doped β-phase NaYF(4), for which there have been no reports of methods capable of producing sub-10 nm nanocrystals. Here we describe conditions for the controlled synthesis of protein-sized β-phase NaYF(4): 20% Yb(3+), 2% Er(3+) nanocrystals, from 4.5 to 15 nm in diameter. The size of the nanocrystals was modulated by varying the concentration of basic surfactants, Y(3+):F(-) ratio, and reaction temperature, variables that also affected their crystalline phase. Increased reaction times favor formation of the desired β-phase nanocrystals while having only a modest effect on nanocrystal size. Core/shell β-phase NaYF(4): 20% Yb(3+), 2% Er(3+)/NaYF(4) nanoparticles less than 10 nm in total diameter exhibit higher luminescence quantum yields than comparable >25 nm diameter core nanoparticles. Single-particle imaging of 9 nm core/shell nanoparticles also demonstrates that they exhibit no measurable photobleaching or blinking. These results establish that small lanthanide-doped upconverting nanoparticles can be synthesized without sacrificing brightness or stability, and these sub-10 nm nanoparticles are ideally suited for single-particle imaging. |
| Databáze: | OpenAIRE |
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