Model of fluorescence intermittency of single colloidal semiconductor quantum dots using multiple recombination...

Area of Science:

• Physical Chemistry
• Materials Science
• Quantum Optics

Background:

• Single colloidal quantum dot fluorescence exhibits power-law distributions in blinking times, a phenomenon not fully explained by existing models.
• Conventional analysis methods for on/off times in fluorescence trajectories are known to be sensitive to threshold choices.

Purpose of the Study:

• To present a novel physical model that resolves the mystery of power-law distributions in colloidal quantum dot fluorescence blinking.
• To explain the threshold dependence observed in conventional analysis methods and other experimental features.

Main Methods:

• The model incorporates nonradiative relaxation of excitons through multiple recombination centers.
• Each recombination center can switch between two quasistationary states.

Main Results:

• The new model naturally explains the observed threshold dependence in blinking time distributions.
• It also accounts for other experimental features like the power-law power spectrum (1/f noise).

Conclusions:

• The proposed physical model offers a comprehensive explanation for single colloidal quantum dot fluorescence blinking dynamics.
• It highlights a critical flaw in conventional threshold analysis and provides a more robust framework for understanding these systems.