Polymer Fibers: Nanoscale Transport and Theory Insights

• Applicants: Professor Dr. Frank Ortmann; Professor Dr. R. Thomas Weitz
• Subject Area: Experimental Condensed Matter Physics ; Experimental and Theoretical Physics of Polymers ; Theoretical Condensed Matter Physics
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 541495916

Organic semiconducting polymers are promising building blocks for novel electronic devices where they are often used to transport charge. Even though electronic transport has been widely investigated, this is typically done in macroscopic geometries. Moreover nanoscale electrical transport in polymers and the intrinsic transport behaviour are not well understood and a matter of controversial debate. Here we address nanoscale transport in a combined experimental and theoretical work on jointly chosen polymer systems. In theory, we will develop a complete ab initio description of the polymer samples including their vibrations and electron-vibrational coupling. We will study comprehensively their electronic and transport properties in the Kubo formalism, develop and compare polymer fiber models regarding their electrical characteristics in which the Coulomb interaction will be modelled as well. In experiment, we will develop a nanoscale contact method for polymer fibers that allow for contact spacings as small as 10 nm and study their properties for various temperatures and investigate photocurrent and terahertz responses, which will also be simulated. The connection of the experimentally determined temperature dependent transport and spectroscopy data to the theoretically generated data including the localization of electronic states, disorder effects, mobility, and effects of vibrations will allow disentangling various effects in this joint project. Therefore, if successful, the project will be a milestone towards a consistent multifaceted description and understanding of electronic transport at the nanoscale.

• DFG Programme: Research Grants