Oxidant-Activated Reactions of Nucleophiles with Silicon Nanocrystals

Mita Dasog, Jonathan R. Thompson, Nathan S Lewis

Research output: Contribution to journalArticle

Abstract

The oxidant-activated reactivity of Si toward nucleophiles was evaluated for Si nanocrystals (Si-NCs) of differing diameters, d. In the presence of ferrocenium as a one-electron, outer-sphere oxidant, d ≥ 8 nm Si-NCs readily reacted with nucleophiles, including methanol, butanol, butylamine, butanoic acid, butylthiol, and diethylphosphine. However, d < 8 nm Si-NCs did not undergo such reactions, and stronger oxidants such as acetylferrocenium or 1,1′-diacetylferrocenium were required. Butylamine-, butylthiol-, and butanol-functionalized d ≥ 8 nm Si-NCs were partially oxidized and exhibited photoluminescence originating from defect states. In contrast, butanoic acid-functionalized Si-NCs were minimally oxidized and displayed core emission resulting from the excitation and relaxation of electrons across the Si-NC bandgap. Diethylphosphine-functionalized Si-NCs were stable only under inert conditions and showed core emission, with the Si-P bonds being highly susceptible to oxidation and rapidly decomposing upon exposure to ambient conditions. The general reactivity is consistent with the redox potential of the one-electron oxidant and the valence band edge position of the Si-NCs. The trends in reactivity thus provide an example of differential chemical reactions of nanoparticles relative to bulk materials, reflecting the differences in electronic structure and the continuum of electronic properties between variously sized Si nanoparticles and bulk Si samples.

Original languageEnglish
Pages (from-to)7002-7013
Number of pages12
JournalChemistry of Materials
Volume29
Issue number16
DOIs
Publication statusPublished - Aug 22 2017

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Nucleophiles
Silicon
Oxidants
Nanocrystals
Butylamines
Butanols
Butyric acid
Butyric Acid
Butenes
Electrons
Nanoparticles
Valence bands
Electronic properties
Electronic structure
Methanol
Chemical reactions
Photoluminescence
Energy gap
Oxidation
Defects

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

Cite this

Oxidant-Activated Reactions of Nucleophiles with Silicon Nanocrystals. / Dasog, Mita; Thompson, Jonathan R.; Lewis, Nathan S.

In: Chemistry of Materials, Vol. 29, No. 16, 22.08.2017, p. 7002-7013.

Research output: Contribution to journalArticle

Dasog, Mita ; Thompson, Jonathan R. ; Lewis, Nathan S. / Oxidant-Activated Reactions of Nucleophiles with Silicon Nanocrystals. In: Chemistry of Materials. 2017 ; Vol. 29, No. 16. pp. 7002-7013.
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