Single Quantum Dot (QD) Velocimetry

We introduce the use of quantum dot (QD) nanoparticles for near-surface velocimetry and provide preliminary data to demonstrate its feasibility. Evanescent wave illumination is used to image the motion of water-soluble (CdSe)ZnS QDs with a core size of 6 nm within a region of order 100 nm of a surface. These particles are an order of magnitude smaller than those typically used to date in nano-PIV studies. Results will be presented for the two in-plane components of the velocity near the surface of a microchannel. This work was supported by the CRC Program of the National Science Foundation, Grant Number CHE-0209898.