title: Picosecond energy transfer and multiexciton transfer outpaces Auger recombination in binary CdSe nanoplatelet solids.
abstract: Fluorescence resonance energy transfer (FRET) enables photosynthetic light harvesting, wavelength downconversion in light-emitting diodes (LEDs), and optical biosensing schemes. The rate and efficiency of this donor to acceptor transfer of excitation between chromophores dictates the utility of FRET and can unlock new device operation motifs including quantum-funnel solar cells, non-contact chromophore pumping from a proximal LED, and markedly reduced gain thresholds. However, the fastest reported FRET time constants involving spherical quantum dots (0.12-1 ns; refs 7-9) do not outpace biexciton Auger recombination (0.01-0.1 ns; ref. 10), which impedes multiexciton-driven applications including electrically pumped lasers and carrier-multiplication-enhanced photovoltaics. Few-monolayer-thick semiconductor nanoplatelets (NPLs) with tens-of-nanometre lateral dimensions exhibit intense optical transitions and hundreds-of-picosecond Auger recombination, but heretofore lack FRET characterizations. We examine binary CdSe NPL solids and show that interplate FRET (∼6-23 ps, presumably for co-facial arrangements) can occur 15-50 times faster than Auger recombination and demonstrate multiexcitonic FRET, making such materials ideal candidates for advanced technologies.
authors.affiliation: Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Clare E
authors.initials: CE
authors.lastname: Rowland
authors.affiliation: Department of Chemistry and James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Igor
authors.initials: I
authors.lastname: Fedin
authors.affiliation: Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, USA.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: Stephen K
authors.initials: SK
authors.lastname: Gray
authors.affiliation: Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, USA.
authors.forename: Alexander O
authors.initials: AO
authors.lastname: Govorov
authors.affiliation: 1] Department of Chemistry and James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA [2] Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: Dmitri V
authors.initials: DV
authors.lastname: Talapin
authors.affiliation: 1] Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA [2] Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Schaller