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O: Fachverband Oberflächenphysik

O 43: Poster: Semiconductor Substrates - Adsorption

O 43.5: Poster

Dienstag, 13. März 2018, 18:15–20:30, Poster A

Cobalt-Pyrphyrin on Cu₂O(111): A promising system for photocatalytic water splitting — •Lisa Grad, Fabio Cossalter, Wolf-D. Zabka, Stephan Schnidrig, Benjamin Probst, Roger Alberto, Zbynek Novotny, Matthias Hengsberger, and Jürg Osterwalder — University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland

Photocatalytic water splitting presents a sustainable way to store solar energy in the form of chemical bonds. For large-scale use, the combination of molecular catalysts supported on abundant substrates is a viable approach. We investigate one such model system: Cobalt-Pyrphyrin (CoPyr) [1] adsorbed on the Cu₂O(111) surface.

Cu₂O(111) is a p-type semiconductor with downward band bending. This property is conserved after adsorbing a layer of CoPyr [2]. The related electrical field supports charge separation by accelerating excited electrons from the Cu₂O to the interface from where they can relax to unoccupied states of CoPyr. There are two different reconstructions of the Cu₂O(111) surface observed: (1x1) and (√3×√3)R30^∘. The structure and stoichiometry of these different surface reconstructions and their influence on electrical properties are still not fully understood, but are expected to influence the surface band bending and charge carrier dynamics. Our current effort centers on investigation of these properties using angle-resolved X-ray photoelectron spectroscopy and time-resolved two-photon photoemission.

[1] Joliat et al., Dalton Transactions 2016 45(4), 1737-1745

[2] Leuenberger et al., Nano Letters 2017 17 (11), 6620-6625