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 language | English |
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Pages (from-to) | 3997-4014 |
Number of pages | 18 |
Journal | Matter |
Volume | 5 |
Issue number | 11 |
DOIs | |
State | Published - 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