Generation of multiple excitons in Ag2S quantum dots: Single high-energy versus multiple-photon excitation

Handle URI:
http://hdl.handle.net/10754/563400
Title:
Generation of multiple excitons in Ag2S quantum dots: Single high-energy versus multiple-photon excitation
Authors:
Sun, Jingya; Yu, Weili; Usman, Anwar; Isimjan, Tayirjan T.; Del Gobbo, Silvano; Alarousu, Erkki; Takanabe, Kazuhiro ( 0000-0001-5374-9451 ) ; Mohammed, Omar F. ( 0000-0001-8500-1130 )
Abstract:
We explored biexciton generation via carrier multiplication (or multiple-exciton generation) by high-energy photons and by multiple-photon absorption in Ag2S quantum dots (QDs) using femtosecond broad-band transient absorption spectroscopy. Irrespective of the size of the QDs and how the multiple excitons are generated in the Ag2S QDs, two distinct characteristic time constants of 9.6-10.2 and 135-175 ps are obtained for the nonradiative Auger recombination of the multiple excitons, indicating the existence of two binding excitons, namely, tightly bound and weakly bound excitons. More importantly, the lifetimes of multiple excitons in Ag 2S QDs were about 1 and 2 orders of magnitude longer than those of comparable size PbS QDs and single-walled carbon nanotubes, respectively. This result is significant because it suggests that by utilizing an appropriate electron acceptor, there is a higher possibility to extract multiple electron-hole pairs in Ag2S QDs, which should improve the performance of QD-based solar cell devices. © 2014 American Chemical Society.
KAUST Department:
KAUST Catalysis Center (KCC); Physical Sciences and Engineering (PSE) Division; KAUST Solar Center (KSC); Chemical Science Program; Materials Science and Engineering Program; Catalysis for Energy Conversion (CatEC)
Publisher:
American Chemical Society (ACS)
Journal:
The Journal of Physical Chemistry Letters
Issue Date:
20-Feb-2014
DOI:
10.1021/jz5000512
Type:
Article
ISSN:
19487185
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; Chemical Science Program; Materials Science and Engineering Program; KAUST Catalysis Center (KCC); KAUST Solar Center (KSC)

Full metadata record

DC FieldValue Language
dc.contributor.authorSun, Jingyaen
dc.contributor.authorYu, Weilien
dc.contributor.authorUsman, Anwaren
dc.contributor.authorIsimjan, Tayirjan T.en
dc.contributor.authorDel Gobbo, Silvanoen
dc.contributor.authorAlarousu, Erkkien
dc.contributor.authorTakanabe, Kazuhiroen
dc.contributor.authorMohammed, Omar F.en
dc.date.accessioned2015-08-03T11:47:38Zen
dc.date.available2015-08-03T11:47:38Zen
dc.date.issued2014-02-20en
dc.identifier.issn19487185en
dc.identifier.doi10.1021/jz5000512en
dc.identifier.urihttp://hdl.handle.net/10754/563400en
dc.description.abstractWe explored biexciton generation via carrier multiplication (or multiple-exciton generation) by high-energy photons and by multiple-photon absorption in Ag2S quantum dots (QDs) using femtosecond broad-band transient absorption spectroscopy. Irrespective of the size of the QDs and how the multiple excitons are generated in the Ag2S QDs, two distinct characteristic time constants of 9.6-10.2 and 135-175 ps are obtained for the nonradiative Auger recombination of the multiple excitons, indicating the existence of two binding excitons, namely, tightly bound and weakly bound excitons. More importantly, the lifetimes of multiple excitons in Ag 2S QDs were about 1 and 2 orders of magnitude longer than those of comparable size PbS QDs and single-walled carbon nanotubes, respectively. This result is significant because it suggests that by utilizing an appropriate electron acceptor, there is a higher possibility to extract multiple electron-hole pairs in Ag2S QDs, which should improve the performance of QD-based solar cell devices. © 2014 American Chemical Society.en
dc.publisherAmerican Chemical Society (ACS)en
dc.subjectAg2S quantum dotsen
dc.subjectAuger recombinationen
dc.subjectexciton multiplicationen
dc.subjectfemtosecond broad-band transient spectroscopyen
dc.titleGeneration of multiple excitons in Ag2S quantum dots: Single high-energy versus multiple-photon excitationen
dc.typeArticleen
dc.contributor.departmentKAUST Catalysis Center (KCC)en
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.contributor.departmentKAUST Solar Center (KSC)en
dc.contributor.departmentChemical Science Programen
dc.contributor.departmentMaterials Science and Engineering Programen
dc.contributor.departmentCatalysis for Energy Conversion (CatEC)en
dc.identifier.journalThe Journal of Physical Chemistry Lettersen
kaust.authorYu, Weilien
kaust.authorUsman, Anwaren
kaust.authorIsimjan, Tayirjan T.en
kaust.authorAlarousu, Erkkien
kaust.authorTakanabe, Kazuhiroen
kaust.authorMohammed, Omar F.en
kaust.authorSun, Jingyaen
kaust.authorDel Gobbo, Silvanoen
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