Hard proof of the NaYF(4)/NaGdF(4) nanocrystal core/shell structure.
Hexagonal-phase NaYF(4)/NaGdF(4) core/shell nanocrystals were synthesized and investigated by X-ray photoelectron spectroscopy (XPS) using tunable synchrotron radiation. Based on the ratio of the Y(3+) 3d to Gd(3+) 4d core level intensities at varying photoelectron kinetic energies, we conclude that Gd(3+) resides predominantly at the surface of the nanocrystals, proving a core/shell structure. These nanocrystals show potential for use as contrast agents in magnetic resonance imaging (MRI) applications and optical imaging.
Abel
Keith A
KA
Department of Chemistry, University of Victoria, P.O. Box 3065, Victoria, British Columbia, Canada, V8W 3V6.
Boyer
John-Christopher
JC
van Veggel
Frank C J M
FC