Role of bond adaptability in the passivation of colloidal quantum dot solids

Handle URI:
http://hdl.handle.net/10754/562981
Title:
Role of bond adaptability in the passivation of colloidal quantum dot solids
Authors:
Thon, Susanna; Ip, Alex; Voznyy, Oleksandr; Levina, Larissa; Kemp, Kyle W.; Carey, Graham H.; Masala, Silvia; Sargent, E. H.
Abstract:
Colloidal quantum dot (CQD) solids are attractive materials for photovoltaic devices due to their low-cost solution-phase processing, high absorption cross sections, and their band gap tunability via the quantum size effect. Recent advances in CQD solar cell performance have relied on new surface passivation strategies. Specifically, cadmium cation passivation of surface chalcogen sites in PbS CQDs has been shown to contribute to lowered trap state densities and improved photovoltaic performance. Here we deploy a generalized solution-phase passivation strategy as a means to improving CQD surface management. We connect the effects of the choice of metal cation on solution-phase surface passivation, film-phase trap density of states, minority carrier mobility, and photovoltaic power conversion efficiency. We show that trap passivation and midgap density of states determine photovoltaic device performance and are strongly influenced by the choice of metal cation. Supported by density functional theory simulations, we propose a model for the role of cations, a picture wherein metals offering the shallowest electron affinities and the greatest adaptability in surface bonding configurations eliminate both deep and shallow traps effectively even in submonolayer amounts. This work illustrates the importance of materials choice in designing a flexible passivation strategy for optimum CQD device performance. © 2013 American Chemical Society.
KAUST Department:
Solar and Photovoltaic Engineering Research Center (SPERC); Materials Science and Engineering Program
Publisher:
American Chemical Society (ACS)
Journal:
ACS Nano
Issue Date:
24-Sep-2013
DOI:
10.1021/nn4021983
PubMed ID:
23909748
Type:
Article
ISSN:
19360851
Sponsors:
This publication is based in part on work supported by an award (KUS-11-009-21) from the King Abdullah University of Science and Technology (KAUST), by the Ontario Research Fund Research Excellence Program and by the Natural Sciences and Engineering Research Council (NSERC) of Canada. The authors thank M. Yuan, L Rollny, E. Palmiano, R. Wolowiec, and D. Kopilovic for their help during the course of the study. Computations were performed on the GPC supercomputer at the SciNet HPC Consortium. SciNet is funded by: the Canada Foundation for Innovation under the auspices of Compute Canada; the Government of Ontario; Ontario Research Fund Research Excellence; and the University of Toronto."
Appears in Collections:
Articles; Materials Science and Engineering Program; Solar and Photovoltaic Engineering Research Center (SPERC)

Full metadata record

DC FieldValue Language
dc.contributor.authorThon, Susannaen
dc.contributor.authorIp, Alexen
dc.contributor.authorVoznyy, Oleksandren
dc.contributor.authorLevina, Larissaen
dc.contributor.authorKemp, Kyle W.en
dc.contributor.authorCarey, Graham H.en
dc.contributor.authorMasala, Silviaen
dc.contributor.authorSargent, E. H.en
dc.date.accessioned2015-08-03T11:17:58Zen
dc.date.available2015-08-03T11:17:58Zen
dc.date.issued2013-09-24en
dc.identifier.issn19360851en
dc.identifier.pmid23909748en
dc.identifier.doi10.1021/nn4021983en
dc.identifier.urihttp://hdl.handle.net/10754/562981en
dc.description.abstractColloidal quantum dot (CQD) solids are attractive materials for photovoltaic devices due to their low-cost solution-phase processing, high absorption cross sections, and their band gap tunability via the quantum size effect. Recent advances in CQD solar cell performance have relied on new surface passivation strategies. Specifically, cadmium cation passivation of surface chalcogen sites in PbS CQDs has been shown to contribute to lowered trap state densities and improved photovoltaic performance. Here we deploy a generalized solution-phase passivation strategy as a means to improving CQD surface management. We connect the effects of the choice of metal cation on solution-phase surface passivation, film-phase trap density of states, minority carrier mobility, and photovoltaic power conversion efficiency. We show that trap passivation and midgap density of states determine photovoltaic device performance and are strongly influenced by the choice of metal cation. Supported by density functional theory simulations, we propose a model for the role of cations, a picture wherein metals offering the shallowest electron affinities and the greatest adaptability in surface bonding configurations eliminate both deep and shallow traps effectively even in submonolayer amounts. This work illustrates the importance of materials choice in designing a flexible passivation strategy for optimum CQD device performance. © 2013 American Chemical Society.en
dc.description.sponsorshipThis publication is based in part on work supported by an award (KUS-11-009-21) from the King Abdullah University of Science and Technology (KAUST), by the Ontario Research Fund Research Excellence Program and by the Natural Sciences and Engineering Research Council (NSERC) of Canada. The authors thank M. Yuan, L Rollny, E. Palmiano, R. Wolowiec, and D. Kopilovic for their help during the course of the study. Computations were performed on the GPC supercomputer at the SciNet HPC Consortium. SciNet is funded by: the Canada Foundation for Innovation under the auspices of Compute Canada; the Government of Ontario; Ontario Research Fund Research Excellence; and the University of Toronto."en
dc.publisherAmerican Chemical Society (ACS)en
dc.subjectbinding energyen
dc.subjectcolloidal quantum dotsen
dc.subjectDFTen
dc.subjectPbS nanocrystalsen
dc.subjectphotovoltaicsen
dc.subjectsurface passivationen
dc.titleRole of bond adaptability in the passivation of colloidal quantum dot solidsen
dc.typeArticleen
dc.contributor.departmentSolar and Photovoltaic Engineering Research Center (SPERC)en
dc.contributor.departmentMaterials Science and Engineering Programen
dc.identifier.journalACS Nanoen
dc.contributor.institutionUniv Toronto, Dept Elect & Comp Engn, Toronto, ON M5S 3G4, Canadaen
kaust.authorMasala, Silviaen

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