Spatially indirect emission in a luminescent nanocrystal molecule

Nano Lett. 2011 Jun 8;11(6):2358-62. doi: 10.1021/nl2007032. Epub 2011 May 19.

Abstract

Recent advances in the synthesis of multicomponent nanocrystals have enabled the design of nanocrystal molecules with unique photophysical behavior and functionality. Here we demonstrate a highly luminescent nanocrystal molecule, the CdSe/CdS core/shell tetrapod, which is designed to have weak vibronic coupling between excited states and thereby violates Kasha's rule via emission from multiple excited levels. Using single particle photoluminescence spectroscopy, we show that in addition to the expected LUMO to HOMO radiative transition, a higher energy transition is allowed via spatially indirect recombination. The oscillator strength of this transition can be experimentally controlled, enabling control over carrier behavior and localization at the nanoscale.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Cadmium Compounds / chemistry*
  • Luminescence*
  • Nanostructures / chemistry*
  • Particle Size
  • Selenium Compounds / chemistry*
  • Sulfides / chemistry*
  • Surface Properties

Substances

  • Cadmium Compounds
  • Selenium Compounds
  • Sulfides
  • cadmium sulfide
  • cadmium selenide