Photon Counting Statistics for Blinking CdSe−ZnS Quantum Dots:  A Lévy Walk Process

Margolin, Gennady; Protasenko, Vladimir; Kuno, Masaru; Barkai, Eli

doi:10.1021/jp061487m

Cited by 69 publications

(82 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…If the duration of the experiment is not long compared with the saturation time 1/⌫, this mean is not well defined, but increases with the duration of the experiment (28)(29)(30). In other words, the magnitude of g (2) ( ) depends on the total time for which data are collected, if this time is less than 1/⌫ (14).…”

Section: Comparison To Modelsmentioning

confidence: 99%

Evidence for a diffusion-controlled mechanism for fluorescence blinking of colloidal quantum dots

Pelton

Smith²,

Scherer

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

162

219

View full text Add to dashboard Cite

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.fluorescence intermittency ͉ power spectrum ͉ nanocrystals H igh-quality, monodisperse semiconductor nanocrystals can be produced in large quantities by colloidal-synthesis techniques (1). These nanocrystals, known as quantum dots (QDs), can exhibit bright luminescence, whose wavelength is controlled by the size of the nanocrystals (2). This property makes colloidal QDs attractive candidates for several applications, including light-emitting diodes (3), solid-state lasers (4), and biological labeling (5, 6). Such applications, however, may be compromised by fluctuations in the QD luminescence. In particular, individual QDs emit light intermittently, switching irregularly between bright (''on'') and dark (''off'') states (7). Widespread interest in this blinking phenomenon was stimulated by the surprising observation that the durations of bright and dark periods follow power-law statistics (8, 9). Specifically, the blinking periods are described by probability densities of the formwith a value of between 0.4 and 1.0. The power-law behavior holds regardless of sample temperature (9), QD size or composition (10), nanoparticle shape (11), or excitation intensity (12). So far, though, experimental studies of QD blinking have been limited in their temporal resolution. A resolution of 200 s was achieved in one of the earliest measurements (8), and a small number of later experimental studies have included analysis of submicrosecond blinking dynamics (14,16,17,41). The remainder of the quantitative characterizations have been restricted to time scales of several milliseconds or longer. In this paper, we report measurements of fluctuations in QD fluorescence on time scales from microseconds to tens of seconds. We observe a change in the fluctuation dynamics for time scales less than several milliseconds.This observation is consistent with the predictions of a class of models where blinking is controlled by slow diffusion of the energies of electron or hole trap states. In these models, the fluorescence of a QD is quenched through the trapping of a carrier, which occurs when the energy of the trap state fulfills a resonance condition. The duration of the blinking periods is determined by the diffusion of the energy of the QD-trap system about this resonance condition. This diffusion-controlled mechanism ...

show abstract

Section: Comparison To Modelsmentioning

confidence: 99%

Evidence for a diffusion-controlled mechanism for fluorescence blinking of colloidal quantum dots

Pelton

Smith²,

Scherer

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

162

219

View full text Add to dashboard Cite

show abstract

“…Then, we can calculate the asymptotic eigenvalues of s 1 | ρ(t) |s 2 by approximating ρ(t) to be a L × L finite-domain matrix. It is simple to calculate the non-null eigenvalues of a matrix of dimension L × L of the form (30). For D = 0 (without dissipation) there is only one non-null eigenvalue:…”

Section: B the Wigner Functionmentioning

confidence: 99%

Non-equilibrium transition from dissipative quantum walk to classical random walk

Nizama¹,

Cáceres²

2012

J. Phys. A: Math. Theor.

View full text Add to dashboard Cite

We have investigated the time-evolution of a free particle in interaction with a phonon thermal bath, using the tight-binding approach. A dissipative quantum walk can be defined and many important non-equilibrium decoherence properties can be investigated analytically. The non-equilibrium statistics of a pure initial state have been studied. Our theoretical results indicate that the evolving wave-packet shows the suppression of Anderson's boundaries (ballistic peaks) by the presence of dissipation. Many important relaxation properties can be studied quantitatively, such as von Neumann's entropy and quantum purity. In addition, we have studied Wigner's function. The time-dependent behavior of the quantum entanglement between a free particle -in the lattice-and the phonon bath has been characterized analytically. This result strongly suggests the non-trivial time-dependence of the off-diagonal elements of the reduced density matrix of the system. We have established a connection between the quantum decoherence and the dissipative parameter arising from interaction with the phonon bath. The time-dependent behavior of quantum correlations has also been pointed out, showing continuous transition from quantum random walk to classical random walk, when dissipation increases.

show abstract

“…The third model proposed by Margolin et al 32 gives an explanation in which the blinking by three-dimensional hopping diffusion of the photoejected electron is in the surrounding media. The positively charged QD stays "off" until the electron returns back.…”

Section: Introductionmentioning

confidence: 99%

Explanation of quantum dot blinking without the long-lived trap hypothesis

2005

View full text Add to dashboard Cite

show abstract

Photon Counting Statistics for Blinking CdSe−ZnS Quantum Dots: A Lévy Walk Process

Cited by 69 publications

References 56 publications

Evidence for a diffusion-controlled mechanism for fluorescence blinking of colloidal quantum dots

Evidence for a diffusion-controlled mechanism for fluorescence blinking of colloidal quantum dots

Non-equilibrium transition from dissipative quantum walk to classical random walk

Explanation of quantum dot blinking without the long-lived trap hypothesis

Contact Info

Product

Resources

About