Influencing quantum dot blinking dynamics: Temporal, chemical and frequency domain studies

COLL 23

David J. Nesbitt, djn@jila.colorado.edu1, Jeffrey J. Peterson2, Thomas A. Baker3, Jessica Rouge2, and Vasiliy Fomenko4. (1) JILA/Department of Chemistry and Biochemistry, JILA/NIST and University of Colorado, Box 440, University of Colorado, Boulder, CO 80309, (2) JILA, National Institute of Standards and Technology and University of Colorado, (3) JILA/Department of Chemistry and Biochemistry, JILA and University of Colorado, Box 440, University of Colorado, Boulder, CO 80309, (4) Landauer, Crystal Growth Division, Stillwater, OK 74074-6413
The combination of confocal microscopy and time correlated single photon counting methods permits study of isolated quantum dot kinetics over an unprecedented dynamic range (< 10-9s to > 103 s). Time permitting, this talk will address recent results on fluorescence blinking dynamics in colloidal ZnS/CdSe quantum dots in the following areas. 1) Photon counting/MLE methods are used to determine fluorescence lifetime trajectories for single QDs with > 1 KHz update rate, providing evidence for both extremely fast and slow fluctuations in quantum yields. 2) Microfluidic control of the solution environment permits study of quantum dot blinking suppression dynamics, which are shown to involve changes in non-radiative and radiative rates. 3) High sensitivity studies as a function of laser power and wavelength indicate exponential deviations from power law behavior in the on-time distributions, providing additional insight into the kinetics and dynamics of QD photoionization.
 

Interfacial Electron Transfer and Solar Energy Conversion: From Molecules to Nanomaterials
8:20 AM-12:00 PM, Sunday, April 6, 2008 Morial Convention Center -- Rm. 226, Oral

Division of Colloid & Surface Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008