Size and bandgap control in the solution-phase synthesis of near-infrared-emitting germanium nanocrystals.

ACS Nano

National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401, USA.

Published: December 2010

AI Article Synopsis

  • A new method for creating alkyl-terminated germanium nanocrystals involves reducing mixtures of GeI(4) and GeI(2).
  • The size of these nanocrystals can be fine-tuned between 2.3 and 11.3 nm by varying the ratio of Ge(IV) to Ge(II) and adjusting the temperature during the process.
  • The study also highlights how the nanocrystals exhibit unique optical properties, including tunable near-infrared absorption and emission, attributed to quantum confinement effects linked to the different reduction temperatures of Ge(II) and Ge(IV).

Article Abstract

We present a novel colloidal synthesis of alkyl-terminated Ge nanocrystals based on the reduction of GeI(4)/GeI(2) mixtures. The size of the nanocrystals (2.3-11.3 nm) was controlled by adjusting both the Ge(IV)/Ge(II) ratio and the temperature ramp rate following reductant injection. The near-infrared absorption (1.6-0.70 eV) and corresponding band-edge emission demonstrate the highly tunable quantum confinement effects in Ge nanocrystals prepared using this mixed-valence precursor method. A mechanism is proposed for the observed size control, which relies upon the difference in reduction temperatures for Ge(II) versus Ge(IV).

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http://dx.doi.org/10.1021/nn102728uDOI Listing

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