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Related Concept Videos

Colloidal precipitates01:09

Colloidal precipitates

The high insolubility of some precipitates can result in an unfavorable relative supersaturation. This can lead to colloidal particles with a large surface-to-mass ratio, where adsorption is promoted. For instance, in the precipitation of silver chloride, silver ions are adsorbed on the surface of the colloidal particles, forming a primary layer. This layer attracts ions of opposite charge (such as nitrate ions), forming a diffuse secondary layer of adsorbed ions. This electric double layer...
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Related Experiment Video

Updated: Jun 24, 2026

Resonance Fluorescence of an InGaAs Quantum Dot in a Planar Cavity Using Orthogonal Excitation and Detection
12:57

Resonance Fluorescence of an InGaAs Quantum Dot in a Planar Cavity Using Orthogonal Excitation and Detection

Published on: October 13, 2017

Trion decay in colloidal quantum dots.

Praket P Jha1, Philippe Guyot-Sionnest

  • 1James Franck Institute, The University of Chicago, 929 East 57th Street, Chicago, Illinois 60637, USA.

ACS Nano
|April 4, 2009
PubMed
Summary
This summary is machine-generated.

Researchers studied charged quantum dots, revealing that the negatively charged exciton (trion T-) has a faster radiative rate than excitons. This finding advances understanding of quantum dot photophysics.

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Time-resolved Photophysical Characterization of Triplet-harvesting Organic Compounds at an Oxygen-free Environment Using an iCCD Camera
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Time-resolved Photophysical Characterization of Triplet-harvesting Organic Compounds at an Oxygen-free Environment Using an iCCD Camera

Published on: December 27, 2018

Related Experiment Videos

Last Updated: Jun 24, 2026

Resonance Fluorescence of an InGaAs Quantum Dot in a Planar Cavity Using Orthogonal Excitation and Detection
12:57

Resonance Fluorescence of an InGaAs Quantum Dot in a Planar Cavity Using Orthogonal Excitation and Detection

Published on: October 13, 2017

Time-resolved Photophysical Characterization of Triplet-harvesting Organic Compounds at an Oxygen-free Environment Using an iCCD Camera
06:08

Time-resolved Photophysical Characterization of Triplet-harvesting Organic Compounds at an Oxygen-free Environment Using an iCCD Camera

Published on: December 27, 2018

Area of Science:

  • Materials Science
  • Quantum Dot Physics
  • Photophysics

Background:

  • Colloidal quantum dots (QDs) like Cadmium Selenide/Cadmium Sulfide (CdSe/CdS) are crucial in optoelectronics.
  • Understanding exciton and trion dynamics is key to optimizing QD performance.
  • Charged excitons, or trions, exhibit unique optical properties.

Purpose of the Study:

  • To measure the radiative and nonradiative decay rates of the negatively charged exciton (trion T-) in CdSe/CdS core/shell quantum dots.
  • To compare the radiative properties of trions with those of excitons and biexcitons.
  • To investigate the influence of core/shell structure on quantum dot decay dynamics.

Main Methods:

  • Fabrication of charged films using colloidal CdSe/CdS core/shell quantum dots.
  • Characterization of QD size (3.5-4.5 nm core diameter) and shell thickness (0.6-1.2 nm).
  • Time-resolved spectroscopic measurements to analyze radiative and nonradiative decay pathways of trions.

Main Results:

  • The radiative decay rate of the trion T- was found to be 2.2 ± 0.4 times faster than that of the exciton, estimated at approximately 10 ns.
  • The measured trion T- lifetime ranged from 0.7 to 1.5 ns.
  • The trion lifetime was observed to be 7.5 ± 1.7 times longer than the biexciton lifetime.

Conclusions:

  • The negatively charged exciton (trion T-) exhibits significantly enhanced radiative properties compared to excitons in CdSe/CdS core/shell quantum dots.
  • The observed lifetimes provide crucial data for modeling charge carrier dynamics in quantum dot systems.
  • These findings contribute to the fundamental understanding of photophysical processes in nanomaterials.