Berlin 2018 – scientific programme

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O: Fachverband Oberflächenphysik

O 96: Focus Session: Molecular Nanostructures on surfaces - New Concepts towards Complex Architectures VI

O 96.9: Talk

Thursday, March 15, 2018, 17:15–17:30, MA 004

Porphyrins at surfaces: effect of film formation on the electronic levels — Osman Baris Malcioglu and •Michel Bockstedte — Chemistry and Physics of Materials, University of Salzburg, Salzburg, Austria

Porphyrins on surfaces are used successfully in various applications such as surface catalysis, lighting and energy harvesting. In order to unravel electronic and photophysical properties of such porphyrin films on surfaces, one first has to identify the contribution of the film’s supramolecular network. Here, we investigate quasiparticle spectrum of amorphous and crystalline porphyrin structure as a model for supramolecular films of H2TPP and MgTPP. We use VdW-DFT and sc-GW approaches (calibrated against NIST data). We show that the crystalline model agrees with the UPS/2PPE spectra [1] better than individual molecules or other porphyrin structures regarding the position of the HOMO and LUMO state. The interaction of the phenyl rings has strong influence one the position and dispersion of quasiparticle levels of the prophyrin film. Our findings confirm that the systematic control of the film crystallisation or the substitution of residues enables an improvement or tuning of the electronic states and thus leads to better performance of devices [3].

[1] A. Classen, et al., Phys. Rev. B 95, 115414 (2017).

[2] M. Gamboa, M. Campos, and L.A. Torres, J. Chem. Thermodynamics 42, 666 (2010)

[3] A. Charisiadis et al., ChemPlusChem, 82, (2017).