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 : 002233Multiple 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. PrezhdoSource :
- ACS nano [ 1936-086X ] ; 2012.
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:
Links toward previous steps (curation, corpus...)
- to stream PubMed, to step Corpus: 001E22
- to stream PubMed, to step Curation: 001E22
- to stream PubMed, to step Checkpoint: 001C58
- to stream Ncbi, to step Merge: 000914
- to stream Ncbi, to step Curation: 000914
- to stream Ncbi, to step Checkpoint: 000914
- to stream Main, to step Merge: 002257
- to stream Main, to step Curation: 002232
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
Ou
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. | ![]() |