Comparison of carrier multiplication yields in PbS and PbSe nanocrystals: The role of competing energy-loss processes

John T. Stewart, Lazaro A. Padilha, M. Mumtaz Qazilbash, Jeffrey M. Pietryga, Aaron G. Midgett, Joseph M. Luther, Matthew C. Beard, Arthur J. Nozik, Victor I Klimov

Research output: Contribution to journalArticle

93 Citations (Scopus)

Abstract

Infrared band gap semiconductor nanocrystals are promising materials for exploring generation III photovoltaic concepts that rely on carrier multiplication or multiple exciton generation, the process in which a single high-energy photon generates more than one electron-hole pair. In this work, we present measurements of carrier multiplication yields and biexciton lifetimes for a large selection of PbS nanocrystals and compare these results to the well-studied PbSe nanocrystals. The similar bulk properties of PbS and PbSe make this an important comparison for discerning the pertinent properties that determine efficient carrier multiplication. We observe that PbS and PbSe have very similar biexciton lifetimes as a function of confinement energy. Together with the similar bulk properties, this suggests that the rates of multiexciton generation, which is the inverse of Auger recombination, are also similar. The carrier multiplication yields in PbS nanocrystals, however, are strikingly lower than those observed for PbSe nanocrystals. We suggest that this implies the rate of competing processes, such as phonon emission, is higher in PbS nanocrystals than in PbSe nanocrystals. Indeed, our estimations for phonon emission mediated by the polar Fröhlich-type interaction indicate that the corresponding energy-loss rate is approximately twice as large in PbS than in PbSe.

Original languageEnglish
Pages (from-to)622-628
Number of pages7
JournalNano Letters
Volume12
Issue number2
DOIs
Publication statusPublished - Feb 8 2012

Fingerprint

multiplication
Nanocrystals
Energy dissipation
nanocrystals
energy dissipation
life (durability)
lead selenide
Excitons
Energy gap
Photons
excitons
Semiconductor materials
Infrared radiation
energy
Electrons
photons
interactions

Keywords

  • Auger recombination
  • Carrier multiplication
  • hot exciton cooling
  • multiple exciton generation

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanical Engineering

Cite this

Stewart, J. T., Padilha, L. A., Qazilbash, M. M., Pietryga, J. M., Midgett, A. G., Luther, J. M., ... Klimov, V. I. (2012). Comparison of carrier multiplication yields in PbS and PbSe nanocrystals: The role of competing energy-loss processes. Nano Letters, 12(2), 622-628. https://doi.org/10.1021/nl203367m

Comparison of carrier multiplication yields in PbS and PbSe nanocrystals : The role of competing energy-loss processes. / Stewart, John T.; Padilha, Lazaro A.; Qazilbash, M. Mumtaz; Pietryga, Jeffrey M.; Midgett, Aaron G.; Luther, Joseph M.; Beard, Matthew C.; Nozik, Arthur J.; Klimov, Victor I.

In: Nano Letters, Vol. 12, No. 2, 08.02.2012, p. 622-628.

Research output: Contribution to journalArticle

Stewart, JT, Padilha, LA, Qazilbash, MM, Pietryga, JM, Midgett, AG, Luther, JM, Beard, MC, Nozik, AJ & Klimov, VI 2012, 'Comparison of carrier multiplication yields in PbS and PbSe nanocrystals: The role of competing energy-loss processes', Nano Letters, vol. 12, no. 2, pp. 622-628. https://doi.org/10.1021/nl203367m
Stewart JT, Padilha LA, Qazilbash MM, Pietryga JM, Midgett AG, Luther JM et al. Comparison of carrier multiplication yields in PbS and PbSe nanocrystals: The role of competing energy-loss processes. Nano Letters. 2012 Feb 8;12(2):622-628. https://doi.org/10.1021/nl203367m
Stewart, John T. ; Padilha, Lazaro A. ; Qazilbash, M. Mumtaz ; Pietryga, Jeffrey M. ; Midgett, Aaron G. ; Luther, Joseph M. ; Beard, Matthew C. ; Nozik, Arthur J. ; Klimov, Victor I. / Comparison of carrier multiplication yields in PbS and PbSe nanocrystals : The role of competing energy-loss processes. In: Nano Letters. 2012 ; Vol. 12, No. 2. pp. 622-628.
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