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Core/Shell Nanocrystal Synthesis in Nonthermal Plasmas

Technology #20160397

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Nanocrystal SynthesisPlasma ReactorGroup IV Materials
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Researchers
Uwe Kortshagen, PhD
Professor, Mechanical Engineering, College of Science and Engineering
External Link (www.me.umn.edu)
Managed By
Larry Micek
Technology Licensing Officer 612-624-9568
Patent Protection

US Patent Pending
Publications
Nonthermal Plasma Synthesis of Core/Shell Quantum Dots: Strained Ge/Si Nanocrystals
ACS Applied Materials & Interfaces, February 7, 2017
Files and Attachments
Non-confidential Summary [PDF]

Plasma Reactor Generates Core/Shell Nanocrystals

An innovative gas-phase method uses a modified plasma reactor to generate core/shell nanocrystals in nonthermal plasmas by afterglow PECVD shell growth. The technology uses afterglow to react a secondary shell onto a primary (core) particle to synthesize group IV nanocrystals that could be used in a variety of applications such as biological imaging, photovoltaics, and energy conversion/storage. Using afterglow limits nanoparticle temperature, which may suppress interdiffusion at the core/shell interface and reduce the degree of alloying. This process, which generates minimal chemical waste, reduces particle agglomeration and does not use any additional ligands, produces epitaxial particles with improved photonic properties and allows for deliberate doping of the nanocrystal core and/or shell.

Tailored for Group IV Materials

Current approaches using solution-phase methods are incompatible with group IV materials, as they often require colloidal stability conferred by organic functionalization, resulting in strong covalent bonds. This gas-phase approach does not require the addition of ligands, minimizes chemical waste, and allows for the deliberate doping of nanocrystal core and/or shell. While this approach is tailored specifically towards the incorporation of group IV materials in heterostructured nanocrystal systems, it may be broadly applicable to any material synthesized via nonthermal plasma (e.g., doped Si, SiGe, ZnO, ZnS, GaN, InP, etc.). These methods synthesize novel, technologically relevant core/shell nanocrystals which have been unproducible in solution.

BENEFITS AND FEATURES:

  • Synthesizes group IV core/shell nanocrystals
  • Minimal chemical waste
  • Reduced particle agglomeration
  • Does not use any additional ligands
  • Produces epitaxial particles with improved photonic properties
  • Reduces energy loss created when particles shift incident light into a separate part of the spectrum
  • May suppress interdiffusion at the core/shell interface and reduce the degree of alloying
  • Allows for deliberate doping of the nanocrystal core and/or shell

APPLICATIONS:

  • Biological imaging
  • Energy storage/conversion
  • May apply to any material synthesized via nonthermal plasma (ex. Doped Si, SiGe, ZnO, GaN, etc)
  • Photovoltaic cells (solar cells)

Phase of Development - Working prototype