Regensburg 2004 – wissenschaftliches Programm

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SYOH: Organic and Hybrid Systems for Future Electronics

SYOH 5: Poster

SYOH 5.23: Poster

Donnerstag, 11. März 2004, 18:00–21:00, B

Electronic Structure and Morphology of 7.8-Dimethylalloxazin on Ag, Au, and HOPG — •Stefan Lach and Christiane Ziegler — Erwin-Schrödinger-Str. 33 67663-Kaiserslautern

Our main emphasis was put on the investigation of the electronic and structural behavior of thin films of the redox-active model substance 7.8-dimethylalloxazin (DMA) on several inorganic surfaces as a prerequisite to construct organic/inorganic molecular electron transfer devices. Alloxazines are capable of building up intermolecular hydrogen-bonded complexes. The optimized structures of the monomer and several dimers were calculated (DFT). The calculated eigenvalues were used to simulate the theoretical photoelectron spectra of the monomer and the dimers. Comparison of the calculations and simulations with the measured data exhibit a small preference for a dimerization. Photoelectron spectroscopy and morphology studies of ultra thin films from DMA on polycrystalline silver and gold as well as on HOPG show distinct differences for these substrates. On HOPG and Au there is no chemical interaction. On HOPG a homogeneous, unstructured layer is formed, but on Au DMA shows island growth with large islands and deep crevices in between. On Ag a new state appears 1.2 eV below the Fermi level and smaller islands are built on the substrate. A calculation and simulation of the photoelectron spectra of a DMA/Ag-complex shows a good correspondence with the experimental results.