title: Evidence for a diffusion-controlled mechanism for fluorescence blinking of colloidal quantum dots.
abstract: Fluorescence blinking in nanocrystal quantum dots is known to exhibit power-law dynamics, and several different mechanisms have been proposed to explain this behavior. We have extended the measurement of quantum-dot blinking by characterizing fluctuations in the fluorescence of single dots over time scales from microseconds to seconds. The power spectral density of these fluctuations indicates a change in the power-law statistics that occurs at a time scale of several milliseconds, providing an important constraint on possible mechanisms for the blinking. In particular, the observations are consistent with the predictions of models wherein blinking is controlled by diffusion of the energies of electron or hole trap states.
authors.affiliation: Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA.
authors.forename: Matthew
authors.initials: M
authors.lastname: Pelton
authors.forename: Glenna
authors.initials: G
authors.lastname: Smith
authors.forename: Norbert F
authors.initials: NF
authors.lastname: Scherer
authors.forename: Rudolph A
authors.initials: RA
authors.lastname: Marcus
mesh_terms: D003102:Colloids; D004058:Diffusion; D008956:Models, Chemical; D011336:Probability; D045663:Quantum Dots; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013499:Surface Properties; D013997:Time Factors
chemical_list: D003102:Colloids