Regularities of intermittent luminescence from spherical and tetrapod-shaped quantum dots

TL;DR

This study investigates the blinking behavior of spherical and tetrapod-shaped quantum dots, revealing power-law distributions and memory effects in their luminescence, which are relevant for nanophotonic applications.

Contribution

It provides a comparative analysis of blinking statistics for different quantum dot shapes, highlighting universal power-law behavior and correlation effects in their luminescence.

Findings

Blinking times follow power-law distributions for both shapes.

Successive on/off times are correlated, indicating a memory effect.

Results align with existing models and inform nanophotonic device development.

Abstract

Intermittent photoluminescence of colloidal core/shell semiconductor nanocrystals of spherical and branched shape was studied under CW-laser excitation. Luminescent multichannel registration system was applied for the fluorescence detection of single quantum dots (QDs) in the polystyrene matrix. Comparative statistical data were obtained and analyzed for nano-sphere CdSe/CdS and nano-tetrapod CdTe/CdSe crystals. It was found that "on-" and "off-" blinking times are distributed according to the power law both for spherical CdSe/CdS and tetrapod shape CdTe/CdSe samples in spite of significant QD formfactor differences. We have also found that regardless of the QD-shape both successive "on"-times and successive "off "-times are correlated and pointing out to the memory effect in the mechanism of QD re-emission comprising the prehistory of exciton birth and recombination. Pearson-s co-efficients were calculated for the correlations of QD-luminescence behavior. Results of experimental measurements were compared with the peculiarities of relevant phe-nomenon models proposed to date. The data obtained can be used for development of nanophotonic applications and nanocomposite light-emitting materials