Aspect ratio dependence of auger recombination and carrier multiplication in PbSe nanorods

Lazaro A. Padilha, John T. Stewart, Richard L. Sandberg, Wan Ki Bae, Weon Kyu Koh, Jeffrey M. Pietryga, Victor I. Klimov

Research output: Contribution to journalArticle

98 Citations (Scopus)

Abstract

Nanomaterials with efficient carrier multiplication (CM), that is, generation of multiple electron-hole pairs by single photons, have been the object of intense scientific interest as potential enablers of high efficiency generation-III photovoltaics. In this work, we explore nanocrystal shape control as a means for enhancing CM. Specifically, we investigate the influence of aspect ratio (ρ) of PbSe nanorods (NRs) on both CM and the inverse of this process, Auger recombination. We observe that Auger lifetimes in NRs increase with increasing particle volume and for a fixed cross-sectional size follow a linear dependence on the NR length. For a given band gap energy, the CM efficiency in NRs shows a significant dependence on aspect ratio and exhibits a maximum at ρ ∼ 6-7 for which the multiexciton yields are a factor of ca. 2 higher than those in quantum dots with a similar bandgap energy. To rationalize our experimental observations, we analyze the influence of dimensionality on both CM and non-CM energy-loss mechanisms and offer possible explanations for the seemingly divergent effects the transition from zero- to one-dimensional confinement has on the closely related processes of Auger recombination and CM.

Original languageEnglish
Pages (from-to)1092-1099
Number of pages8
JournalNano letters
Volume13
Issue number3
DOIs
Publication statusPublished - Mar 13 2013

Keywords

  • Auger recombination
  • Nanocrystal
  • carrier multiplication
  • multiexciton
  • nanorod
  • quantum dot

ASJC Scopus subject areas

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

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    Padilha, L. A., Stewart, J. T., Sandberg, R. L., Bae, W. K., Koh, W. K., Pietryga, J. M., & Klimov, V. I. (2013). Aspect ratio dependence of auger recombination and carrier multiplication in PbSe nanorods. Nano letters, 13(3), 1092-1099. https://doi.org/10.1021/nl304426y