Title: Interface structure of semiconducting polymer films probed with synchrotron radiation

Abstract: Semiconducting polymers are interesting materials that are being developed for a wide range of applications including polymer solar cells, polymer field-effect transistors and polymer light emitting diodes. The thin film microstructure of semiconducting polymers strongly influences the performance of such devices. Being long chain molecules with a planar backbone, the in-plane orientation of polymer chains and their “edge-on” vs. “face-on” orientation are important in determining device function. For polymer field-effect transistors, since charge transport occurs with a few nanometers of the polymer/dielectric interface, interface structure is critically important.

In this presentation I will describe the application of synchrotron radiation to study interface structure in semiconducting polymer thin films. In particular, studies utilising near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and grazing incidence wide-angle X-ray scattering (GIWAXS) will be presented showing the solution-processed semiconducting polymers can exhibit surface microstructure that is distinct to the film “bulk.” Such knowledge is important in being able to critically assess the impact of film microstructure of device function.