Regensburg 2016 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 90: Poster III
HL 90.21: Poster
Thursday, March 10, 2016, 16:00–19:00, Poster A
Influence of preparation parameters on film morphology and charge transfer in doped organic semiconductors investigated by IR spectroscopy — •Sebastian Beck1,2, Lars Müller2,3, Vipilan Sivanesan1,2, and Annemarie Pucci1,2 — 1Universität Heidelberg, Kirchhoff-Institut für Physik — 2InnovationLab GmbH, Heidelberg — 3Technische Universität Braunschweig, Institut für Hochfrequenztechnik
Molecular orientation as well as a homogeneous dopant distribution are known to be important for efficient charge transfer (CT) in doped organic semiconductors. Both properties can be varied in a certain range by changing preparation parameters. In this study, the influences of different preparation parameters on film morphology and CT in doped organic semiconductors are investigated. In films deposited onto a cooled substrate in vacuum a reduced diffusion of the evaporated molecules on the substrate surface occurs. The reduced thermal energy of the deposited molecules freezes non-equilibrium molecular orientations of dopant and matrix molecules which prevent efficient CT. During warming up to room temperature a molecular rearrangement takes place facilitating CT in the doped layer. This effect is studied and identified by means of in-situ IR spectroscopy. The morphologies of solution processed thin films are varied by spin coating doped layers from solvents with different polarities and evaporation temperatures. Observed differences in UV-Vis spectra of doped P3HT solutions and thin layers prepared from these solutions indicate a pre-definition of the thin film morphology already in the liquid phase.