Photon correlations in colloidal quantum dot molecules controlled by the neck barrier

Somnath Koley, Jiabin Cui, Yossef E. Panfil, Yonatan Ossia, Adar Levi, Einav Scharf, Lior Verbitsky, Uri Banin

Research output: Contribution to journalArticlepeer-review

Abstract

The charge redistribution upon optical excitation of various necked homodimer colloidal quantum dot molecules (CQDMs) is investigated using single-particle emission spectroscopy. By tuning the hybridization of the electron wavefunctions at a fixed center-to-center distance through controlling the neck girth, we reveal two coupling limits: on one hand, a “connected-but-confined” situation where neighboring CQDs are weakly fused to each other, manifesting a weak-coupling regime, and on the other hand, a “connected-and-delocalized” situation where the neck is filled beyond the facet size, leading to a rod-like architecture manifesting strong coupling. The interplay between the radiative and non-radiative Auger decays of these states turns emitted photons from the CQDMs in the weak-coupling regime highly bunched unlike CQD monomers, while the antibunching is regained at the strong-coupling regime. This work sets an analogy for the artificial molecule CQDMs with regular molecules, where the two distinct regimes of weak and strong coupling correspond to ionic- or covalent-type bonding, respectively.

Original languageEnglish
Pages (from-to)3997-4014
Number of pages18
JournalMatter
Volume5
Issue number11
DOIs
StatePublished - 2 Nov 2022

Keywords

  • Auger process
  • MAP2: Benchmark
  • colloidal quantum dots
  • electronic coupling
  • photon antibunching
  • single-particle spectroscopy

All Science Journal Classification (ASJC) codes

  • General Materials Science

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