Aerosol Generated Core-shell Nanoparticles: Synthesis and Characterization

Forskningsoutput: AvhandlingLicentiatavhandling

270 Nedladdningar (Pure)

Sammanfattning

Aerosol technology is a promising platform to synthesize and study core-shell
nanoparticles - a multi-elemental nanoparticle system where the core of one material is covered by a shell of another material. In this thesis, two distinctly separate strategies have been explored to synthesize core-shell nanoparticles by aerosol methods: physical vapor deposition (PVD) by evaporation, and surface segregation via thermal treatment.

Using a novel aerosol PVD design with a local heater to decouple shell material heating from the aerosol, Zn condensation on Au core particles was studied and compared to a simple model based on kinetic gas theory and Comsol simulations. Elemental characterization with electron microscopy did, however, reveal an AuZn alloy instead of the intended core-shell morphology. Growth was additionally found to be limited by homogenous nucleation of Zn vapor.

In contrast, tube furnace heating of spark discharge generated CuAg agglomerates demonstrated the possibility to obtain both a quasi-Janus and a core-shell nanoparticle morphology, simply by tuning the furnace temperature to control the surface segregation. The chemical composition of core and shell phases determined by machine learning algorithms applied to elemental maps of the particles were in congruence with X-ray Photoelectron Spectroscopy measurements. Further elemental characterization of the spark discharge generated CuAg particles revealed a low inter-particle compositional variance, the reason of which remains to be investigated.
Originalspråkengelska
KvalifikationLicentiat
Tilldelande institution
  • Fasta tillståndets fysik
Handledare
  • Deppert, Knut, handledare
  • Messing, Maria, Biträdande handledare
  • Eom, Namsoon, Biträdande handledare
  • Ek Rosén, Martin, Biträdande handledare
  • Westerström, Rasmus, Biträdande handledare
Tilldelningsdatum2021 juni 10
Förlag
StatusPublished - 2021 juni 10

Ämnesklassifikation (UKÄ)

  • Nanoteknik

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