MersV1, Main, Exploration, bibRecord, 002232

Multiple exciton generation and recombination dynamics in small Si and CdSe quantum dots: an ab initio time-domain study.

Identifieur interne : 002232 ( Main/Exploration ); précédent : 002231; suivant : 002233

Multiple exciton generation and recombination dynamics in small Si and CdSe quantum dots: an ab initio time-domain study.

Auteurs : Kim Hyeon-Deuk [Japon] ; Oleg V. Prezhdo

Source :

ACS nano [ 1936-086X ] ; 2012.

RBID : pubmed:22214339

Abstract

Multiple exciton generation and recombination (MEG and MER) dynamics in semiconductor quantum dots (QDs) are simulated using ab initio time-dependent density functional theory in combination with nonadiabatic molecular dynamics. The approach differs from other MEG and MER theories because it provides atomistic description, employs time-domain representation, allows for various dynamical regimes, and includes electron-phonon interactions. MEG rapidly accelerates with energy, reflecting strong energy dependence of double exciton (DE) density of states. At early times, MEG is Gaussian rather than exponential. Exponential dynamics, assumed in rate theories, starts at a later time and becomes more important in larger QDs. Phonon-assisted MEG is observed at energies below the purely electronic threshold, particularly in the presence of high-frequency ligand vibrations. Coupling to phonons is essential for MER since higher-energy DEs must relax to recombine into single excitons (SEs), and SEs formed during MERs must lose some of their energy to avoid recreating DEs. MER simulated starting from a DE is significantly slower than MER involving an optical excitation of a SE, followed by MEG and then MER. The latter time scale agrees with experiment, emphasizing the importance of quantum-mechanical superpositions of many DEs for efficient MER. The detailed description of the interplay between MEG and MER coupled to phonons provides important insights into the excited state dynamics of semiconductor QDs and nanoscale materials in general.

DOI: 10.1021/nn2038884
PubMed: 22214339

Affiliations:

Le document en format XML

<record><TEI><teiHeader><fileDesc><titleStmt><title xml:lang="en">Multiple exciton generation and recombination dynamics in small Si and CdSe quantum dots: an ab initio time-domain study.</title>
<author><name sortKey="Hyeon Deuk, Kim" sort="Hyeon Deuk, Kim" uniqKey="Hyeon Deuk K" first="Kim" last="Hyeon-Deuk">Kim Hyeon-Deuk</name>
<affiliation wicri:level="4"><nlm:affiliation>Department of Chemistry, Kyoto University, Kyoto 606-8502, Japan. kim@kuchem.kyoto-u.ac.jp</nlm:affiliation>
<country xml:lang="fr">Japon</country>
<wicri:regionArea>Department of Chemistry, Kyoto University, Kyoto 606-8502</wicri:regionArea>
<orgName type="university">Université de Kyoto</orgName>
<placeName><settlement type="city">Kyoto</settlement>
<region type="prefecture">Région du Kansai</region>
</placeName>
</affiliation>
</author>
<author><name sortKey="Prezhdo, Oleg V" sort="Prezhdo, Oleg V" uniqKey="Prezhdo O" first="Oleg V" last="Prezhdo">Oleg V. Prezhdo</name>
</author>
</titleStmt>
<publicationStmt><idno type="wicri:source">PubMed</idno>
<date when="2012">2012</date>
<idno type="RBID">pubmed:22214339</idno>
<idno type="pmid">22214339</idno>
<idno type="doi">10.1021/nn2038884</idno>
<idno type="wicri:Area/PubMed/Corpus">001E22</idno>
<idno type="wicri:explorRef" wicri:stream="PubMed" wicri:step="Corpus" wicri:corpus="PubMed">001E22</idno>
<idno type="wicri:Area/PubMed/Curation">001E22</idno>
<idno type="wicri:explorRef" wicri:stream="PubMed" wicri:step="Curation">001E22</idno>
<idno type="wicri:Area/PubMed/Checkpoint">001C58</idno>
<idno type="wicri:explorRef" wicri:stream="Checkpoint" wicri:step="PubMed">001C58</idno>
<idno type="wicri:Area/Ncbi/Merge">000914</idno>
<idno type="wicri:Area/Ncbi/Curation">000914</idno>
<idno type="wicri:Area/Ncbi/Checkpoint">000914</idno>
<idno type="wicri:Area/Main/Merge">002257</idno>
<idno type="wicri:Area/Main/Curation">002232</idno>
<idno type="wicri:Area/Main/Exploration">002232</idno>
</publicationStmt>
<sourceDesc><biblStruct><analytic><title xml:lang="en">Multiple exciton generation and recombination dynamics in small Si and CdSe quantum dots: an ab initio time-domain study.</title>
<author><name sortKey="Hyeon Deuk, Kim" sort="Hyeon Deuk, Kim" uniqKey="Hyeon Deuk K" first="Kim" last="Hyeon-Deuk">Kim Hyeon-Deuk</name>
<affiliation wicri:level="4"><nlm:affiliation>Department of Chemistry, Kyoto University, Kyoto 606-8502, Japan. kim@kuchem.kyoto-u.ac.jp</nlm:affiliation>
<country xml:lang="fr">Japon</country>
<wicri:regionArea>Department of Chemistry, Kyoto University, Kyoto 606-8502</wicri:regionArea>
<orgName type="university">Université de Kyoto</orgName>
<placeName><settlement type="city">Kyoto</settlement>
<region type="prefecture">Région du Kansai</region>
</placeName>
</affiliation>
</author>
<author><name sortKey="Prezhdo, Oleg V" sort="Prezhdo, Oleg V" uniqKey="Prezhdo O" first="Oleg V" last="Prezhdo">Oleg V. Prezhdo</name>
</author>
</analytic>
<series><title level="j">ACS nano</title>
<idno type="eISSN">1936-086X</idno>
<imprint><date when="2012" type="published">2012</date>
</imprint>
</series>
</biblStruct>
</sourceDesc>
</fileDesc>
<profileDesc><textClass></textClass>
</profileDesc>
</teiHeader>
<front><div type="abstract" xml:lang="en">Multiple exciton generation and recombination (MEG and MER) dynamics in semiconductor quantum dots (QDs) are simulated using ab initio time-dependent density functional theory in combination with nonadiabatic molecular dynamics. The approach differs from other MEG and MER theories because it provides atomistic description, employs time-domain representation, allows for various dynamical regimes, and includes electron-phonon interactions. MEG rapidly accelerates with energy, reflecting strong energy dependence of double exciton (DE) density of states. At early times, MEG is Gaussian rather than exponential. Exponential dynamics, assumed in rate theories, starts at a later time and becomes more important in larger QDs. Phonon-assisted MEG is observed at energies below the purely electronic threshold, particularly in the presence of high-frequency ligand vibrations. Coupling to phonons is essential for MER since higher-energy DEs must relax to recombine into single excitons (SEs), and SEs formed during MERs must lose some of their energy to avoid recreating DEs. MER simulated starting from a DE  is significantly slower than MER involving an optical excitation of a SE, followed by MEG and then MER. The latter time scale agrees with experiment, emphasizing the importance of quantum-mechanical superpositions of many DEs for efficient MER. The detailed description of the interplay between MEG and MER coupled to phonons provides important insights into the excited state dynamics of semiconductor QDs and nanoscale materials in general.</div>
</front>
</TEI>
<affiliations><list><country><li>Japon</li>
</country>
<region><li>Région du Kansai</li>
</region>
<settlement><li>Kyoto</li>
</settlement>
<orgName><li>Université de Kyoto</li>
</orgName>
</list>
<tree><noCountry><name sortKey="Prezhdo, Oleg V" sort="Prezhdo, Oleg V" uniqKey="Prezhdo O" first="Oleg V" last="Prezhdo">Oleg V. Prezhdo</name>
</noCountry>
<country name="Japon"><region name="Région du Kansai"><name sortKey="Hyeon Deuk, Kim" sort="Hyeon Deuk, Kim" uniqKey="Hyeon Deuk K" first="Kim" last="Hyeon-Deuk">Kim Hyeon-Deuk</name>
</region>
</country>
</tree>
</affiliations>
</record>

Pour manipuler ce document sous Unix (Dilib)

EXPLOR_STEP=$WICRI_ROOT/Sante/explor/MersV1/Data/Main/Exploration

HfdSelect -h $EXPLOR_STEP/biblio.hfd -nk 002232 | SxmlIndent | more

HfdSelect -h $EXPLOR_AREA/Data/Main/Exploration/biblio.hfd -nk 002232 | SxmlIndent | more

Pour mettre un lien sur cette page dans le réseau Wicri

{{Explor lien
   |wiki=    Sante
   |area=    MersV1
   |flux=    Main
   |étape=   Exploration
   |type=    RBID
   |clé=     pubmed:22214339
   |texte=   Multiple exciton generation and recombination dynamics in small Si and CdSe quantum dots: an ab initio time-domain study.
}}

Pour générer des pages wiki

HfdIndexSelect -h $EXPLOR_AREA/Data/Main/Exploration/RBID.i   -Sk "pubmed:22214339" \
       | HfdSelect -Kh $EXPLOR_AREA/Data/Main/Exploration/biblio.hfd   \
       | NlmPubMed2Wicri -a MersV1

This area was generated with Dilib version V0.6.33.
Data generation: Mon Apr 20 23:26:43 2020. Site generation: Sat Mar 27 09:06:09 2021

Serveur d'exploration MERS

Multiple exciton generation and recombination dynamics in small Si and CdSe quantum dots: an ab initio time-domain study.

Multiple exciton generation and recombination dynamics in small Si and CdSe quantum dots: an ab initio time-domain study.

Source :

Abstract

Links toward previous steps (curation, corpus...)

Le document en format XML

Pour manipuler ce document sous Unix (Dilib)

Pour mettre un lien sur cette page dans le réseau Wicri

Pour générer des pages wiki

	Serveur d'exploration MERS
	Attention, ce site est en cours de développement ! Attention, site généré par des moyens informatiques à partir de corpus bruts. Les informations ne sont donc pas validées.