Berlin 2008 – scientific programme

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SYSA: Symposium Tayloring Organic Interfaces: Molecular Structures and Applications

SYSA 2: Organic Interface Structure and Growth

SYSA 2.1: Invited Talk

Tuesday, February 26, 2008, 10:45–11:15, H 0105

Organic film growth and organic-metal interfaces — •Norbert Koch — Humboldt-Universität zu Berlin, Institut f. Physik, Berlin, Germany

The structure, morphology, and electronic properties of thin films formed by conjugated organic molecules are key factors determining the function and efficiency of organic (opto-) electronic devices. Molecules chemisorbed on metal surfaces can undergo significant conformation changes, often facilitated by a hybridization of molecular and metal electron wavefunctions. The resulting energy levels at such interfaces are determined by a complex interplay of molecular orientation, charge transfer, and conformation dependent dipoles, which will be exemplified for strong electron acceptor molecules on coinage metal surfaces. The modification of metal surfaces with electron acceptors can be used to control the energy level alignment of subsequently deposited organic layers. Thin organic films on insulating substrates are of interest for organic field effect transistors. Co-deposited rod-like conjugated molecules can form new crystalline intercalated structures with electronic properties significantly different from those of the pure materials. It will be shown that the appropriate combination of two different molecules facilitates (i) control over the energy levels, and (ii) widely tunable charge transport properties.