Influence of Electric Fields on the Electron Transport in Donor–Acceptor Polymers

The influence of an electric field on different properties of the donor–acceptor polymer diketo-pyrrolo-pyrrole bithiophene thienothiophene (DPPT-TT) that are essential for the charge transport process is studied. The main focus is on whether the transport in DPPT-TT-based organic transistors can be tuned by electric fields in the gate direction. The considered electric fields are in the range 108–1010 V m–1. We show that strong electric fields (∼109 V m–1) which are parallel to the polymer backbone can influence the reorganization energy in a Markus-type approach. Weaker electric fields parallel to the polymer backbone result in minimal changes to the reorganization energy. The coupling element of DPPT-TT shows a pronounced affinity to be influenced by electric fields in the charge transport direction independent of the field strength.