Delayed Exciton Emission and Its Relation to Blinking in CdSe Quantum Dots

Freddy T. Rabouw, Marko Kamp, Relinde Moes, Daniel R. Gamelin, A. Femius Koenderink, A Meijerink, Daniël Vanmaekelbergh*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

The efficiency and stability of emission from semiconductor nanocrystal quantum dots (QDs) is negatively affected by "blinking" on the single-nanocrystal level, that is, random alternation of bright and dark periods. The time scales of these fluctuations can be as long as many seconds, orders of magnitude longer than typical lifetimes of exciton states in QDs. In this work, we investigate photoluminescence from QDs delayed over microseconds to milliseconds. Our results prove the existence of long-lived charge-separated states in QDs. We study the properties of delayed emission as a direct way to learn about charge carrier separation and recovery of the exciton state. A new microscopic model is developed to connect delayed emission to exciton recombination and blinking from which we conclude that bright periods in blinking are in fact not characterized by uninterrupted optical cycling as often assumed.

Original languageEnglish
Pages (from-to)7718-7725
Number of pages8
JournalNano Letters
Volume15
Issue number11
DOIs
Publication statusPublished - 11 Nov 2015

Keywords

  • blinking
  • charge carrier trapping
  • colloidal quantum dot
  • excited state dynamics
  • Nanocrystal

Fingerprint

Dive into the research topics of 'Delayed Exciton Emission and Its Relation to Blinking in CdSe Quantum Dots'. Together they form a unique fingerprint.

Cite this