Spectral shift, electronic coupling and exciton delocalization in nanocrystal dimers: insights from all-atom electronic structure computations

Coden, Maurizio; Checchi, Pietro De; Fresch, Barbara

doi:10.1039/d0nr05601d

Cited by 8 publications

(5 citation statements)

References 93 publications

(114 reference statements)

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“…20,29 Moreover, strongly coupled dimers of colloidal QDs have been designed and the possibility of excitonic delocalization over the two units has been discussed, based on both theoretical and experimental evidences. 50,75–79 How weak and strong-coupling are associated with specific spectral features in A-2DES maps is a critical issue which is left for future work.…”

Section: Discussionmentioning

confidence: 99%

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Simulating action-2D electronic spectroscopy of quantum dots: insights on the exciton and biexciton interplay from detection-mode and time-gating

Bruschi

Gallina

Fresch

2022

Phys. Chem. Chem. Phys.

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Section: Discussionmentioning

confidence: 99%

“…This journal is © the Owner Societies 2022 been discussed, based on both theoretical and experimental evidences. 50,[75][76][77][78][79] How weak and strong-coupling are associated with specific spectral features in A-2DES maps is a critical issue which is left for future work.…”

Section: Conflicts Of Interestmentioning

confidence: 99%

Simulating action-2D electronic spectroscopy of quantum dots: insights on the exciton and biexciton interplay from detection-mode and time-gating

Bruschi

Gallina

Fresch

2022

Phys. Chem. Chem. Phys.

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“…This requires the controlled placement of a second quantum system in close proximity. 13 The chemical bond serves as a basis of molecule formation with electronically coupled atomic states, enabling tunneling of the electrons and delocalization throughout the new hybridized molecular state. 2 Similarly, close proximity of two quantum dots with a minimal barrier engenders hybridized electron wave function delocalized throughout the double quantum dot structure, forming a quantum molecule.…”

Section: From Artificial Atom To Artificial Moleculesmentioning

confidence: 99%

“…The observations of the artificial atom character of CQDs inspired the formation of quantum dot molecules where the creation of hybridized excitons can impose novel synergistic functionalities, relevant to numerous applications including in quantum technologies. This requires the controlled placement of a second quantum system in close proximity . The chemical bond serves as a basis of molecule formation with electronically coupled atomic states, enabling tunneling of the electrons and delocalization throughout the new hybridized molecular state .…”

Section: From Artificial Atom To Artificial Moleculesmentioning

confidence: 99%

Coupled Colloidal Quantum Dot Molecules

et al. 2021

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Conspectus Electronic coupling and hence hybridization of atoms serves as the basis for the rich properties for the endless library of naturally occurring molecules. Colloidal quantum dots (CQDs) manifesting quantum strong confinement possess atomic-like characteristics with s and p electronic levels, which popularized the notion of CQDs as artificial atoms. Continuing this analogy, when two atoms are close enough to form a molecule so that their orbitals start overlapping, the orbitals energies start to split into bonding and antibonding states made out of hybridized orbitals. The same concept is also applicable for two fused core–shell nanocrystals in close proximity. Their band edge states, which dictate the emitted photon energy, start to hybridize, changing their electronic and optical properties. Thus, an exciting direction of “artificial molecules” emerges, leading to a multitude of possibilities for creating a library of new hybrid nanostructures with novel optoelectronic properties with relevance toward diverse applications including quantum technologies. The controlled separation and the barrier height between two adjacent quantum dots are key variables for dictating the magnitude of the coupling energy of the confined wave functions. In the past, coupled double quantum dot architectures prepared by molecular beam epitaxy revealed a coupling energy of few millielectron volts, which limits the applications to mostly cryogenic operation. The realization of artificial quantum molecules with sufficient coupling energy detectable at room temperature calls for the use of colloidal semiconductor nanocrystal building blocks. Moreover, the tunable surface chemistry widely opens the predesigned attachment strategies as well as the solution processing ability of the prepared artificial molecules, making the colloidal nanocrystals as an ideal candidate for this purpose. Despite several approaches that demonstrated enabling of the coupled structures, a general and reproducible method applicable to a broad range of colloidal quantum materials is needed for systematic tailoring of the coupling strength based on a dictated barrier This Account addresses the development of nanocrystal chemistry to create coupled colloidal quantum dot molecules and to study the controlled electronic coupling and their emergent properties. The simplest nanocrystal molecule, a homodimer formed from two core/shell nanocrystal monomers, in analogy to homonuclear diatomic molecules, serves as a model system. The shell material of the two CQDs is structurally fused, resulting in a continuous crystal. This lowers the potential energy barrier, enabling the hybridization of the electronic wave functions. The direct manifestation of the hybridization reflects on the band edge transition shifting toward lower energy and is clearly resolved at room temperature. The hybridization energy within the single homodimer molecule is strongly correl...

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“…They found that the dithiocarbamate molecule generates new electronic states close to the band edges of the CdSe QDs, which corroborated the earlier observation. Many other computational studies have also contributed to rationalize the exciton delocalization at the interface of QD-molecule composites. − …”

Section: Introductionmentioning

confidence: 99%

Interfacial Charge Transfer in Photoexcited QD-Molecule Composite of Tetrahedral CdSe Quantum Dot Coupled with Carbazole

Samuthirapandi,

Durairaj,

Sarkar

2024

ACS Appl. Mater. Interfaces

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Spectral shift, electronic coupling and exciton delocalization in nanocrystal dimers: insights from all-atom electronic structure computations

Abstract: Delocalization of excitons promoted by electronic coupling between clusters or quantum dots (QD) changes the dynamical processes in nanostructured aggregates enhancing energy transport. A spectroscopic shift of the absorption spectrum...

Cited by 8 publications

References 93 publications

Simulating action-2D electronic spectroscopy of quantum dots: insights on the exciton and biexciton interplay from detection-mode and time-gating

Simulating action-2D electronic spectroscopy of quantum dots: insights on the exciton and biexciton interplay from detection-mode and time-gating

Coupled Colloidal Quantum Dot Molecules

Interfacial Charge Transfer in Photoexcited QD-Molecule Composite of Tetrahedral CdSe Quantum Dot Coupled with Carbazole

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