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Physical synthesis of nanoparticles: some case studies for a rational design of advanced materials

Mercoledý 3 maggio 2017 – 15.00, aula Seminari, S3 Cnr Nano, Dipartimento FIM, Modena

Relatore: Sergio D'Addato
Abstract: Synthesis, study and applications of NanoParticles (NPs) have been playing a major role in material science and technology over the last 20 years, although some important examples of NP presence in manufactured goods can be dated back to ancient history [1]. Realization of NPs with chemical methods is nowadays mainstream, because of the cost effectiveness and scalability. Nevertheless, physical synthesis with a bottom-up approach presents some advantages, especially when a “fine tuning” of the NP properties is required. Physical synthesis can be single-step and ligand-free, and these characteristics can result in a more accurate analysis of the NP structure and of their electronic and magnetic behavior. During the last years we developed a laboratory for the NP synthesis with a magnetron based gas aggregation source (GAS) and a quadrupole mass filter. The versatility of the NP source allowed us to prepare and study different types of NPs. Moreover, co-deposition and sequential layer deposition methods have been used to obtain core@shell NPs. These methods gave us the possibility of realizing non-native oxide shells [2], and to investigate metal@metal oxide core@shell NPs by varying independently the core diameter and the shell thickness. Three case studies will be reported:

  • An investigation of structure and magnetic properties of Ni@NiO and Ni@CoO NP films, as model systems for exploiting the exchange bias effect to “beat the superparamagnetic limit” [3,4].
  • A detailed TEM, EELS AND XPS analysis of CeO2-x NPs synthesized with different procedures, to obtain information on the role of size, defect density and sites in reduction-oxidation cycles of this material, that plays an important role in catalysis and energy conversion and storage [5].
  • A joint experimental and theoretical study of structure and plasmonic properties of Ag and Ag@MgO NP films, of potential interest in photovoltaic [6,7].
[1] D.J. Barber and I. C. Freeston, Archaeometry 32 (1990) 33.
[2] S. D’Addato et al., J. Phys. Chem C 115 (2011) 14044.
[3] J. A. De Toro et al., Phys. Rev. Lett. 115 (2015) 057201.
[4] M. C. Spadaro et al., Nanotechnology 26 (2015) 405704.
[5] M. C. Spadaro et al., Nanotechnology 27 (2016) 425705.
[6] H. A. Atwater and A. Polman, Nature Mat. 9 (2010) 205.
[7] S. D’Addato et al., Beilstein J. Nanotechnol. 6 (2015) 404.

Ospiti: Massimo Rontani

[Ultimo aggiornamento: 03/05/2017 13:20:04]