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dc.contributor.authorSun, Bin
dc.contributor.authorVafaie, Maral
dc.contributor.authorLevina, Larissa
dc.contributor.authorWei, Mingyang
dc.contributor.authorDong, Yitong
dc.contributor.authorGao, Yajun
dc.contributor.authorKung, Hao Ting
dc.contributor.authorBiondi, Margherita
dc.contributor.authorProppe, Andrew H.
dc.contributor.authorChen, Bin
dc.contributor.authorChoi, Min-Jae
dc.contributor.authorSagar, Laxmi Kishore
dc.contributor.authorVoznyy, Oleksandr
dc.contributor.authorKelley, Shana O.
dc.contributor.authorLaquai, Frédéric
dc.contributor.authorLu, Zhenghong
dc.contributor.authorHoogland, Sjoerd
dc.contributor.authorGarcía de Arquer, F Pelayo
dc.contributor.authorSargent, E.
dc.date.accessioned2020-04-07T14:08:03Z
dc.date.available2020-04-07T14:08:03Z
dc.date.issued2020-03-31
dc.date.submitted2020-02-13
dc.identifier.citationSun, B., Vafaie, M., Levina, L., Wei, M., Dong, Y., Gao, Y., … Sargent, E. H. (2020). Ligand-Assisted Reconstruction of Colloidal Quantum Dots Decreases Trap State Density. Nano Letters. doi:10.1021/acs.nanolett.0c00638
dc.identifier.issn1530-6984
dc.identifier.issn1530-6992
dc.identifier.doi10.1021/acs.nanolett.0c00638
dc.identifier.urihttp://hdl.handle.net/10754/662456
dc.description.abstractIncreasing the power conversion efficiency (PCE) of colloidal quantum dot (CQD) solar cells has relied on improving the passivation of CQD surfaces, enhancing CQD coupling and charge transport, and advancing device architecture. The presence of hydroxyl groups on the nanoparticle surface, as well as dimers—fusion between CQDs—has been found to be the major source of trap states, detrimental to optoelectronic properties and device performance. Here, we introduce a CQD reconstruction step that decreases surface hydroxyl groups and dimers simultaneously. We explored the dynamic interaction of charge carriers between band-edge states and trap states in CQDs using time-resolved spectroscopy, showing that trap to ground-state recombination occurs mainly from surface defects in coupled CQD solids passivated using simple metal halides. Using CQD reconstruction, we demonstrate a 60% reduction in trap density and a 25% improvement in charge diffusion length. These translate into a PCE of 12.5% compared to 10.9% for control CQDs.
dc.description.sponsorshipThis work was supported by Ontario Research Fund-Research Excellence program (ORF7 Ministry of Research and Innovation, Ontario Research Fund-Research Excellence Round 7), by the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under Award No. OSR-2018-CRG7-373702 and Award No. OSR-2018-CARF/CCF-3079, and by the Natural Sciences and Engineering Research Council (NSERC) of Canada. The authors acknowledge the financial support from QD Solar.
dc.publisherAmerican Chemical Society (ACS)
dc.relation.urlhttps://pubs.acs.org/doi/10.1021/acs.nanolett.0c00638
dc.rightsThis document is the Accepted Manuscript version of a Published Work that appeared in final form in Nano Letters, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acs.nanolett.0c00638.
dc.titleLigand-Assisted Reconstruction of Colloidal Quantum Dots Decreases Trap State Density
dc.typeArticle
dc.contributor.departmentKAUST Solar Center (KSC)
dc.contributor.departmentMaterial Science and Engineering Program
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
dc.identifier.journalNano Letters
dc.rights.embargodate2021-03-31
dc.eprint.versionPost-print
dc.contributor.institutionDepartment of Electrical and Computer Engineering, University of Toronto, 10 King’s College Road, Toronto, Ontario M5S 3G4, Canada
dc.contributor.institutionDepartment of Material Science and Engineering, University of Toronto, 184 College Street, Toronto, Ontario M5S 3E4, Canada
dc.contributor.institutionDepartment of Chemistry, University of Toronto, Toronto, Ontario M5S 3G4, Canada
dc.contributor.institutionDepartment of Pharmaceutical Science, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3G4, Canada
kaust.personGao, Yajun
kaust.personLaquai, Frederic
kaust.grant.numberOSR-2018-CARF/CCF-3079
dc.date.accepted2020-03-25
refterms.dateFOA2020-04-08T05:48:59Z
kaust.acknowledged.supportUnitCCF
kaust.acknowledged.supportUnitOffice of Sponsored Research (OSR)
dc.date.published-online2020-03-31
dc.date.published-print2020-05-13


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