Abstract

We report time-resolved single molecule fluorescence imaging of individual CdSe quantum dots that are functionalized with oligomeric conjugated organic ligands. The fluorescence intensity trajectories from these composite nanostructures display both a strong degree of blinking suppression and interesting intensity fluctuations with recurrence times on the order of 10-60 seconds (quantified by Fourier transform analysis). In addition, Time-Tagged-Time-Resolved (TTTR) fluorescence measurements of the fluorescence decay rate of individual hybrid nanostructures indicate significantly modified non-radiative decay rates relative to conventional ZnS-capped CdSe quantum dots. Modelling of fluorescence intensity trajectories using a diffusive reaction coordinate model shows that slow fluctuations in electron energies (1Se, 1Pe) can give rise to the recurrences via modified Auger-assisted hole-trapping rates. We briefly discuss a possible ligand-induced mechanism for this observed behavior.

© 2007 APS

PDF Article
More Like This
Photon Antibunching From Hybrid Quantum Dot/Conjugated Organic Composite Nanostructures

M. Y. Odoi, K. T. Early, P. K. Sudeep, T. Emrick, and M. D. Barnes
LSTuJ3 Laser Science (LS) 2009

Directional Absorption and Emission in Hybrid Polymer-Quantum Dot Nanostructures Studied by Scanning Probe and Fluorescence Microscopy

K. T. Early, K. D. McCarthy, M. Y. Odoi, P. K. Sudeep, T. Emrick, and M. D. Barnes
FWE5 Frontiers in Optics (FiO) 2008

Periodic Intensity Fluctuations in Functionalized Semiconductor Quantum Dots: Correlation with Ligand Coverage

K. T. Early, K. D. McCarthy, N. I. Hammer, M. Y. Odoi, R. Tangirala, T. Emrick, and M. D. Barnes
JWC37 Frontiers in Optics (FiO) 2007