Emory M Chan

US Patent:

20150241349, Aug 27, 2015

Filed:

Feb 12, 2015

Appl. No.:

14/620644

Inventors:

Bruce E. Cohen - San Francisco CA, US
James P. Schuck - Oakland CA, US
Daniel J. Gargas - Berkeley CA, US
Emory M. Chan - Oakland CA, US
Alexis D. Ostrowski - Maumee OH, US
Jeffrey J. Urban - Emeryville CA, US
Delia J. Milliron - Oakland CA, US

Assignee:

The Regents of the University of California - Oakland CA

International Classification:

G01N 21/64
C09K 11/77

Abstract:

Various embodiments of the invention describe the synthesis of upconverting nanoparticles (UCNPs), lanthanide-doped hexagonal β-phase sodium yttrium fluoride NaYF:Er/Ybnanocrystals, less than 10 nanometers in diameter that are over an order of magnitude brighter under single-particle imaging conditions than existing compositions, allowing visualization of single UCNPs as small (d=4.8 nm) as fluorescent proteins. We use Advanced single-particle characterization and theoretical modeling is demonstrated to find that surface effects become critical at diameters under 20 nm, and that the fluences used in single-molecule imaging change the dominant determinants of nanocrystal brightness. These results demonstrate that factors known to increase brightness in bulk experiments lose importance at higher excitation powers, and that, paradoxically, the brightest probes under single-molecule excitation are barely luminescent at the ensemble level.