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dc.contributor.authorGounko, Iourien
dc.contributor.authorBradley, Louiseen
dc.date.accessioned2011-04-19T16:27:04Z
dc.date.available2011-04-19T16:27:04Z
dc.date.issued2011en
dc.date.submitted2011en
dc.identifier.citationLunz, M, Bradley, AL, Gerard, VA, Byrne, SJ, Gun'ko, YK, Lesnyak, V, Gaponik, N, Concentration dependence of Forster resonant energy transfer between donor and acceptor nanocrystal quantum dot layers: Effect of donor-donor interactions, PHYSICAL REVIEW B, 83, 11, 115423, 2011en
dc.identifier.otherYen
dc.identifier.urihttp://hdl.handle.net/2262/54961
dc.descriptionPUBLISHEDen
dc.description.abstractThe influences of donor and acceptor concentrations on Forster resonant energy transfer (FRET) in a separated donor-acceptor quantum dot bilayer structure have been investigated. Donor intra-ensemble energy transfer is shown to have an impact on the donor-acceptor FRET efficiency in the bilayer structure. At high donor concentrations the FRET distance dependence and the acceptor concentration dependence in the separated donor-acceptor layer structure agree well with theories developed for FRET between randomly distributed, homogeneous donor and acceptor ensembles. However, discrepancies between measurement and theory are found at low donor concentrations. A donor concentration study shows that the FRET efficiency decreases with increasing donor concentration even though a donor concentration-independent FRET efficiency is predicted by standard theory. The observed dependence of the FRET efficiency on the donor concentration can be explained within the FRET rate model, for a constant, donor concentration independent FRET rate, by taking into account the concentration dependent donor reference lifetime arising from intra-donor ensemble FRET. This shows that the decrease in the FRET efficiency with increasing donor concentration is not a signature of a change in the donor-acceptor FRET rate, but due to the competition of the donor-acceptor and donor-donor energy transfer for the higher energy donors. As the intra-donor ensemble FRET represents another decay mechanism, the donor quantum yield for the higher energy donors decreases with increasing donor quantum dot (QD) concentration, as can also be seen from the redshift of the donor emission spectrum. Using this concentration dependent donor quantum yield in the calculation of the Forster radius, the FRET theory for homogeneous donor and acceptor ensembles can be modified to include the effect of the donor intra-ensemble transfer and to correctly describe the trends and absolute values of the measured FRET efficiencies as a function of the donor and the acceptor concentrations. These results show that in QD systems where intra-donor ensemble FRET is as important as the radiative and nonradiative donor decay mechanisms, the FRET rate rather than the FRET efficiency more appropriately characterizes the donor-acceptor FRET. By fitting with the rate model, FRET rates as high as (1.2 ns)(-1) have been determined for the structures presented here.en
dc.description.sponsorshipThis work was financially supported by Science Foundation Ireland 05/PICA/1797.en
dc.language.isoenen
dc.relation.ispartofseriesPHYSICAL REVIEW Ben
dc.relation.ispartofseries83en
dc.relation.ispartofseries11, 115423en
dc.rightsYen
dc.subjectCondensed matter physicsen
dc.subjectForster resonant energy transfer (FRETen
dc.titleConcentration dependence of Forster resonant energy transfer between donor and acceptor nanocrystal quantum dot layers: Effect of donor-donor interactionsen
dc.typeJournal Articleen
dc.type.supercollectionscholarly_publicationsen
dc.type.supercollectionrefereed_publicationsen
dc.identifier.peoplefinderurlhttp://people.tcd.ie/bradlelen
dc.identifier.peoplefinderurlhttp://people.tcd.ie/igounkoen
dc.identifier.rssinternalid72661en
dc.subject.TCDThemeNanoscience & Materialsen
dc.identifier.rssurihttp://dx.doi.org/10.1103/PhysRevB.83.115423en
dc.identifier.orcid_id0000-0002-9399-8628en
dc.contributor.sponsorScience Foundation Ireland (SFI)en
dc.contributor.sponsorGrantNumber05/PICA/1797en


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