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dc.contributor.authorZhitomirsky, David
dc.contributor.authorKramer, Illan J.
dc.contributor.authorLabelle, André J.
dc.contributor.authorFischer, Armin H.
dc.contributor.authorDebnath, Ratan K.
dc.contributor.authorPan, Jun
dc.contributor.authorBakr, Osman
dc.contributor.authorSargent, E. H.
dc.date.accessioned2015-08-03T09:44:32Z
dc.date.available2015-08-03T09:44:32Z
dc.date.issued2012-01-24
dc.identifier.issn15306984
dc.identifier.pmid22257205
dc.identifier.doi10.1021/nl2041589
dc.identifier.urihttp://hdl.handle.net/10754/562089
dc.description.abstractThe size-effect tunability of colloidal quantum dots enables facile engineering of the bandgap at the time of nanoparticle synthesis. The dependence of effective bandgap on nanoparticle size also presents a challenge if the size dispersion, hence bandgap variability, is not well-controlled within a given quantum dot solid. The impact of this polydispersity is well-studied in luminescent devices as well as in unipolar electronic transport; however, the requirements on monodispersity have yet to be quantified in photovoltaics. Here we carry out a series of combined experimental and model-based studies aimed at clarifying, and quantifying, the importance of quantum dot monodispersity in photovoltaics. We successfully predict, using a simple model, the dependence of both open-circuit voltage and photoluminescence behavior on the density of small-bandgap (large-diameter) quantum dot inclusions. The model requires inclusion of trap states to explain the experimental data quantitatively. We then explore using this same experimentally tested model the implications of a broadened quantum dot population on device performance. We report that present-day colloidal quantum dot photovoltaic devices with typical inhomogeneous linewidths of 100-150 meV are dominated by surface traps, and it is for this reason that they see marginal benefit from reduction in polydispersity. Upon eliminating surface traps, achieving inhomogeneous broadening of 50 meV or less will lead to device performance that sees very little deleterious impact from polydispersity. © 2012 American Chemical Society.
dc.description.sponsorshipThis publication is based in part on work supported by Award No. KUS-11-009-21 made by King Abdullah University of Science and Technology (KAUST), by the Ontario Research Fund Research Excellence Program, by the Natural Sciences and Engineering Research Council (NSERC) of Canada, and by Angstrom Engineering and Innovative Technology. D.Z., I.J.K., and R.D. acknowledge the financial support through the NSERC CGS D Scholarship, the Ontario Graduate Scholarship and the MITACS Elevate Strategic Fellowship, respectively. The authors would also like to acknowledge the technical assistance and scientific guidance of L. Brzozowski, E. Palmiano, R. Wolowiec, D. Kopilovic, and S. Hoogland.
dc.publisherAmerican Chemical Society (ACS)
dc.subjectbandgap engineering
dc.subjectcolloidal quantum dot
dc.subjectEnergy landscaping
dc.subjectphotovoltaics
dc.subjectpolydispersity
dc.subjectsolar cell
dc.titleColloidal quantum dot photovoltaics: The effect of polydispersity
dc.typeArticle
dc.contributor.departmentFunctional Nanomaterials Lab (FuNL)
dc.contributor.departmentKAUST Catalysis Center (KCC)
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.contributor.institutionUniv Toronto, Dept Elect & Comp Engn, Toronto, ON M5S 3G4, Canada
kaust.personPan, Jun
kaust.personBakr, Osman M.
kaust.grant.numberKUS-11-009-21
dc.date.published-online2012-01-24
dc.date.published-print2012-02-08


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