Berlin 2012 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 39: Topical Session Theory meets Experiment IV - Batteries, Thermoelectrics and Thermal Barrier Coatings

MM 39.1: Topical Talk

Mittwoch, 28. März 2012, 16:15–16:45, TC 006

Electrode interfaces in organic electronics — •Karsten Albe, Peter Agoston, Andre Wachau, Mareike Hohmann, and Andreas Klein — TU Darmstadt, Inst. für Materialwissenschaft, Petersenstr. 32, D-64287 Darmstadt

Sn-doped In₂O₃ (ITO) is a transparent conducting oxide with a high transparency in the visible range of the optical spectrum and high electrical conductivity, which is widely used as transparent electrode material for organic light emitting diodes and organic photovoltaics. Due to the orientation dependent ionization potential, a polycrystalline ITO film will exhibit a laterally varying work function, which results in an inhomogeneous charge injection into organic semiconductors when used as electrode material. Thus, a detailed understanding of the surface structure and thermodynamics is a prerequisite for optimizing the transparent electrode. In this contribution the thermodynamic stability of several experimentally observed low-index surfaces of bcc indium oxide (In2O3) are investigated by means of density functional theory calculations. The influence of hydrogen, water, n-type dopants (Sn), as well as the in-plane lattice strain are studied and compared to results of STM-studies on single crystalline samples. The computed data are also contrasted with results from photoelectron spectrocscopy on magetron-sputtered layers and explain, why the orientation dependence of the work function will become even more pronounced when oxygen plasma treatments are performed.