Article (Scientific journals)
Coherent Exciton Dynamics in Ensembles of Size-Dispersed CdSe Quantum Dot Dimers Probed via Ultrafast Spectroscopy: A Quantum Computational Study
Gattuso, Hugo; Fresch, Barbara; Levine, D. Raphael et al.
2020In Applied Sciences, 10 (4), p. 1328
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Keywords :
exciton dynamics CdSe quantum dots dimers size dispersion effects coherent electronic dynamics pump-probe transient absorption spectroscopy
Abstract :
[en] Interdot coherent excitonic dynamics in nanometric colloidal CdSe quantum dots (QD) dimers lead to interdot charge migration and energy transfer. We show by electronic quantum dynamical simulations that the interdot coherent response to ultrashort fs laser pulses can be characterized by pump-probe transient absorption spectroscopy in spite of the inevitable inherent size dispersion of colloidal QDs. The latter, leading to a broadening of the excitonic bands, induce accidental resonances that actually increase the efficiency of the interdot coupling. The optical electronic response is computed by solving the time-dependent Schrodinger equation including the interaction with the oscillating electric field of the pulses for an ensemble of dimers that differ by their size. The excitonic Hamiltonian of each dimer is parameterized by the QD size and interdot distance, using an effective mass approximation. Local and charge transfer excitons are included in the dimer basis set. By tailoring the QD size, the excitonic bands can be tuned to overlap and thus favor interdot coupling. Computed pump-probe transient absorption maps averaged over the ensemble show that the coherence of excitons in QD dimers that lead to interdot charge migration can survive size disorder and could be observed in fs pump-probe, four-wave mixing, or covariance spectroscopy.
Research center :
MolSys - Molecular Systems - ULiège
Disciplines :
Chemistry
Author, co-author :
Gattuso, Hugo ;  Université de Liège - ULiège > Département de chimie (sciences) > Laboratoire de chimie physique théorique
Fresch, Barbara
Levine, D. Raphael
Remacle, Françoise  ;  Université de Liège - ULiège > Département de chimie (sciences) > Laboratoire de chimie physique théorique
Language :
English
Title :
Coherent Exciton Dynamics in Ensembles of Size-Dispersed CdSe Quantum Dot Dimers Probed via Ultrafast Spectroscopy: A Quantum Computational Study
Publication date :
2020
Journal title :
Applied Sciences
eISSN :
2076-3417
Publisher :
MDPI, Basel, Switzerland
Volume :
10
Issue :
4
Pages :
1328
Peer reviewed :
Peer Reviewed verified by ORBi
European Projects :
H2020 - 766563 - COPAC - Coherent Optical Parallel Computing
Name of the research project :
MONACOP
Funders :
F.R.S.-FNRS - Fonds de la Recherche Scientifique [BE]
CE - Commission Européenne [BE]
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since 26 January 2021

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