Vibrations and their Impact on Electronic and Transport Properties of Organic Materials

Frank Ortmann (TU Dresden)

Dec 09. 2019, 14:40 — 15:00

Vibrations are not only omnipresent in molecular materials, but are particularly of great importance there due to the softness of the materials and the strong electron-phonon coupling. One possibility to investigate this interaction is to study the low-energy edge of optical absorption spectra. Intriguingly also this spectral range is critical for the performance of organic solar cells and lacks an in-depth understanding for organic materials. We have recently observed a strong dependence of low-energy absorption features on the organic material under study, which we associated to molecular flexibility and polaron deformation. Here we report our efforts in developing an approach to simulate the excitonic density of states and low-energy absorption features including low-frequency molecular vibrations in prototypical donor-acceptor blends featuring charge-transfer excitons. We will also discuss how a distinguished treatment of strong coupling molecular vibrations of different energies leads to an improved description of charge transport.

Further Information
ESI Boltzmann Lecture Hall
Associated Event:
Polarons in the 21st Century (Workshop)
Jozef Devreese (U Antwerpen)
Cesare Franchini (U of Vienna)
Georg Kresse (U of Vienna)
Jacques Tempere (U Antwerpen)