Nonexponential “blinking” kinetics of single CdSe quantum dots: A universal power law behavior

Kuno, Masaru; Fromm, David P.; Hamann, Hendrik F.; Gallagher, A. C.; Nesbitt, David J.

doi:10.1063/1.480896

Cited by 671 publications

(807 citation statements)

References 24 publications

Supporting

Mentioning

740

Contrasting

Unclassified

Order By: Relevance

“…The dots have a mean diameter of 5 nm and an emission spectrum centered near 600 nm. The fluorescence rate is highly dynamic, exhibiting ''blinking'' and sudden changes in quantum yield (QY), in agreement with previous observations [8,22,23]. When a quantum dot is ''on'' and in a high QY state, a typical count rate of 2 10 4 sec ÿ1 is measured with 300 nW of illumination power.…”

supporting

confidence: 74%

Tip-Enhanced Fluorescence Microscopy at 10 Nanometer Resolution

et al. 2004

View full text Add to dashboard Cite

We demonstrate unambiguously that the field enhancement near the apex of a laser-illuminated silicon tip decays according to a power law that is moderated by a single parameter characterizing the tip sharpness. Oscillating the probe in intermittent contact with a semiconductor nanocrystal strongly modulates the fluorescence excitation rate, providing robust optical contrast and enabling excellent background rejection. Laterally encoded demodulation yields images with <10 nm spatial resolution, consistent with independent measurements of tip sharpness. DOI: 10.1103/PhysRevLett.93.180801 PACS numbers: 07.79.Fc, 42.50.Hz, 61.46.+w, 78.67.Bf The potential of near-field microscopy to optically resolve structure well below the diffraction limit has excited physicists, chemists, and biologists for almost 20 years. Conventional near-field scanning optical microscopy (NSOM) uses the light forced through a small metal aperture to locally excite or detect an optical response. The spatial resolution in NSOM is limited to 30 -50 nm by the penetration depth of light into the metal aperture. More recently, apertureless-NSOM (ANSOM) techniques were developed which leverage the strong enhancement of an externally applied optical field at the apex of a sharp tip for local excitation of the sample [1][2][3][4][5][6][7][8][9][10][11]. The promised advantage of ANSOM is that spatial resolution should be limited only by tip sharpness (typically 10 nm). The resolution in most previous ANSOM experiments, however, was at best marginally better than NSOM and was inferior to expectations based on tip sharpness alone. Further, the external field used to induce enhancement led to a substantial background signal and to assertions that one-photon fluorescence is not appropriate for ANSOM [12,13]. These experiments fell short of their potential because they maintained a tip-sample gap of several nanometers, and thus did not thoroughly exploit the tightly confined enhancement.Here, we demonstrate an ANSOM technique that fully exploits the available contrast and leads to spatial resolution that is limited only by tip sharpness. The problems associated with a tip-sample gap are overcome by oscillating the probe in intermittent contact with the sample. The detected signal is then composed of a modulated near-field portion that is superimposed on the far-field background. Subsequent demodulation decouples the two components and thus strongly elevates the near-field signal relative to the background. With this technique, we measured <10 nm lateral resolution via one-photon fluorescence imaging of isolated quantum dots, consistent with independent measurements of tip sharpness. The measured resolution is >3 times better than previous reports for quantum dots using one-photon fluorescence [8,9], and is 2 times better than previous measurements using higher-order optical processes (two-photon fluorescence [6], Raman scattering [4,5]) despite predictions to the contrary [12,13].To better understand the advantages of this technique and to facilitate ...

show abstract

supporting

confidence: 74%

Tip-Enhanced Fluorescence Microscopy at 10 Nanometer Resolution

et al. 2004

View full text Add to dashboard Cite

show abstract

“…This probability distribution is no more a Poisson distribution with mean equal to the value of the local excitation PSF, but a convolution of this and the "on" and "off" time probability distributions. Simulations performed using various probability distributions reported in the literature (exponential 22 or power law 23 ), and as observed in our laboratory (data not shown), yielded uncertainties compatible with the values obtained by bootstrap estimation. To experimentally assess the performance of colocalization studies using nanocrystals, we used the simpler APD (Fig.…”

Section: Colocalization Resultssupporting

confidence: 62%

“…raster scanning) imaging. Indeed, they exhibit a complex pattern of intermittency [20][21][22][23] , which results in a patchy image of the excitation PSF, as built up from the fluorescence emitted by a single nanocrystal. Figure 3 gives an example of multicolor imaging of a mixture of 4 batches exhibiting striking example of "blinking" nanocrystals.…”

Section: Spectral Properties and Multicolor Imaging Of Nanocrystalmentioning

confidence: 99%

<title>Ultrahigh-resolution multicolor colocalization of single fluorescent nanocrystals</title>

et al. 2001

View full text Add to dashboard Cite

A new method for in vitro and possibly in vivo ultrahigh-resolution colocalization and distance measurement between biomolecules is described, based on semiconductor nanocrystal probes. This ruler bridges the gap between FRET and far-field (or near-field scanning optical microscope) imaging and has a dynamic range from few nanometers to tens of micrometers. The ruler is based on a stage-scanning confocal microscope that allows the simultaneous excitation and localization of the excitation point-spreadfunction (PSF) of various colors nanocrystals while maintaining perfect registry between the channels. Fit of the observed diffraction and photophysics-limited images of the PSFs with a two-dimensional Gaussian allows one to determine their position with nanometer accuracy. This new high-resolution tool opens new windows in various molecular, cell biology and biotechnology applications.

show abstract

“…At the transition to the nonstationary phase (ν ¼ 2), the stationary result diverges. periods and remain dark during others [63][64][65]. The durations of these on periods and off periods are found to be distributed according to a power law whose exponent is such that the average on and off time is infinite (i.e., of the order of the measurement time), leading to aging in the intensity autocorrelation function [7,66].…”

Section: Blinking Quantum Dots and Lévy Walkmentioning

confidence: 99%

Scaling Green-Kubo Relation and Application to Three Aging Systems

et al. 2014

View full text Add to dashboard Cite

The Green-Kubo formula relates the spatial diffusion coefficient to the stationary velocity autocorrelation function. We derive a generalization of the Green-Kubo formula that is valid for systems with longrange or nonstationary correlations for which the standard approach is no longer valid. For the systems under consideration, the velocity autocorrelation function hvðt þ τÞvðtÞi asymptotically exhibits a certain scaling behavior and the diffusion is anomalous, hx 2 ðtÞi ≃ 2D ν t ν . We show how both the anomalous diffusion coefficient D ν and the exponent ν can be extracted from this scaling form. Our scaling GreenKubo relation thus extends an important relation between transport properties and correlation functions to generic systems with scale-invariant dynamics. This includes stationary systems with slowly decaying power-law correlations, as well as aging systems, systems whose properties depend on the age of the system. Even for systems that are stationary in the long-time limit, we find that the long-time diffusive behavior can strongly depend on the initial preparation of the system. In these cases, the diffusivity D ν is not unique, and we determine its values, respectively, for a stationary or nonstationary initial state. We discuss three applications of the scaling Green-Kubo relation: free diffusion with nonlinear friction corresponding to cold atoms diffusing in optical lattices, the fractional Langevin equation with external noise recently suggested to model active transport in cells, and the Lévy walk with numerous applications, in particular, blinking quantum dots. These examples underline the wide applicability of our approach, which is able to treat very different mechanisms of anomalous diffusion.

show abstract

Nonexponential “blinking” kinetics of single CdSe quantum dots: A universal power law behavior

Cited by 671 publications

References 24 publications

Tip-Enhanced Fluorescence Microscopy at 10 Nanometer Resolution

Tip-Enhanced Fluorescence Microscopy at 10 Nanometer Resolution

<title>Ultrahigh-resolution multicolor colocalization of single fluorescent nanocrystals</title>

Scaling Green-Kubo Relation and Application to Three Aging Systems

Contact Info

Product

Resources

About