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Home - Events - European XFEL Seminars - What one can learn applying photoelectron spectroscopy to free, in situ fabricated nanoparticles out of metal oxides and sulphides

Seminar

What one can learn applying photoelectron spectroscopy to free, in situ fabricated nanoparticles out of metal oxides and sulphides

Speaker: Maxim Tchaplyguine (MAX IV Laboratory, Lund, Sweden)

Date: 19th June 2017 13:00

Location: Campus Schenefeld, Main Building (XHQ), Room 1.173

Unique information can be obtained when synchrotron-based photoelectron spectroscopy (PES) is applied to free nanoparticles fabricated in situ. In the presented work the electronic structure and component distribution have been characterized with atomic layer resolution for: 1) catalysis-relevant gold-oxide particles; 2) semiconductor lead-sulphide particles actual for Quantum Dot Solar Cells; and 3) semiconductor nanoparticles containing tin oxides.
The nanoparticles have been fabricated by a novel method based on vapour aggregation and reactive magnetron sputtering. The method allows fine tuning of the chemical composition and component distribution of the particles which are about 10 nm. The PES characterization of these particles has been performed “on-the-fly” – in a beam in vacuum. This has allowed avoiding any influence of a substrate or a ligand on the particle inherent properties.
The joint of the fabrication and characterization techniques have brought the results which would be difficult to obtain otherwise. For example, different gold oxidation states have been reached. Our PbS nanoparticles allow producing films in which the particles are not covered by organic capping, the latter causing poor charge transport. Our PES study on tin-oxide nanoparticles has resolved an old controversy of materials science: in contrast to a common opinion a chemical shift for SnO2 and SnO, the shift value for Sn(IV)-three times larger than that for Sn(II)-oxide.