Letter | Published:

Picosecond energy transfer and multiexciton transfer outpaces Auger recombination in binary CdSe nanoplatelet solids

Nature Materials volume 14, pages 484489 (2015) | Download Citation

Abstract

Fluorescence resonance energy transfer (FRET) enables photosynthetic light harvesting1, wavelength downconversion in light-emitting diodes2 (LEDs), and optical biosensing schemes3. 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 cells4, non-contact chromophore pumping from a proximal LED5, and markedly reduced gain thresholds6. However, the fastest reported FRET time constants involving spherical quantum dots (0.12–1 ns; refs 7, 8, 9) do not outpace biexciton Auger recombination (0.01–0.1 ns; ref. 10), which impedes multiexciton-driven applications including electrically pumped lasers11 and carrier-multiplication-enhanced photovoltaics12,13. Few-monolayer-thick semiconductor nanoplatelets (NPLs) with tens-of-nanometre lateral dimensions14 exhibit intense optical transitions14 and hundreds-of-picosecond Auger recombination15,16, 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 recombination15,16 and demonstrate multiexcitonic FRET, making such materials ideal candidates for advanced technologies.

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Acknowledgements

This work was performed, in part, at the Center for Nanoscale Materials, a US Department of Energy, Office of Science, Office of Basic Energy Sciences User Facility under Contract No. DE-AC02-06CH11357. C.E.R. acknowledges support by a National Science Foundation Graduate Research Fellowship under Grant No. DGE-0824162. D.V.T. acknowledges support by the NSF MRSEC Program under Award Number DMR 14-20709 and thanks the II-VI Foundation and Keck Foundation. H.Z. and A.O.G. acknowledge support by the US Army Research Office under grant number W911NF-12-1-0407 and the Volkswagen Foundation (Germany).

Author information

Affiliations

  1. Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA

    • Clare E. Rowland
    •  & Richard D. Schaller
  2. Department of Chemistry and James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA

    • Igor Fedin
    •  & Dmitri V. Talapin
  3. Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701, USA

    • Hui Zhang
    •  & Alexander O. Govorov
  4. Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439, USA

    • Stephen K. Gray
    • , Dmitri V. Talapin
    •  & Richard D. Schaller

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Contributions

Sample synthesis and electron microscopy were performed by I.F. and D.V.T. Optical measurements and data analysis were performed by C.E.R. and R.D.S. Computational work was performed by H.Z., A.O.G. and S.K.G. All authors contributed to the writing of the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Richard D. Schaller.

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DOI

https://doi.org/10.1038/nmat4231

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