Energy Structure of CdSe/CdTe Type II Colloidal Quantum Dots - Do Phonon Bottlenecks Remain for Thick Shells?

Research output: Research - peer-reviewArticle

  • External authors:
  • Charles T. Smith
  • Edward J. Tyrrell
  • Jacek Miloszewski
  • Thomas Walsh
  • Musa Cadirci
  • Robert Page
  • Paul O'Brien
  • Stanko Tomic

Abstract

The excitonic structure of CdSe/CdTe type II colloidal quantum dots is predicted using a model based on k.p theory and the many{particle configuration interaction method, with proper treatment of the polarization effects at the core{shell interface and at the dot surface. The separation of energy levels in the conduction band is examined and used to identify phonon bottlenecks, and how these evolve as the shell thickness is increased. Bottlenecks are found to persist both above and below the threshold for multiple exciton generation for all the shell thicknesses investigated. The overall electron cooling rate is thus expected to fall as the shell thickness is increased, and this is confirmed experimentally using ultrafast transient absorption measurements.

Bibliographical metadata

Original languageEnglish
JournalSolar Energy Materials & Solar Cells
DOIs
StatePublished - 2015

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