Regensburg 2019 – scientific programme

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DS: Fachverband Dünne Schichten

DS 14: Poster

DS 14.46: Poster

Tuesday, April 2, 2019, 17:00–20:00, Poster E

Pathways of polymer degradation of PCPDTBT and PDTSTzTz — •Andreas Frueh¹, Ulf Dettinger¹, Heiko Peisert¹, Hans-Joachim Egelhaaf², and Thomas Chassé¹ — ¹Universität Tübingen, IPTC, Auf der Morgenstelle 18 D-72076 Tübingen, Germany — ²ZAE Bayern, Auf AEG, Bau 16, 1. OG, Fürther Str. 250, D-90429 Nürnberg

The photodegradation kinetics of two prototypical low-bandgap polymers (PCPDTBT and PDTSTzTz) in thin films upon illumination with light with wavelenths between 365 and 700 nm have been studied using UV/vis and fluorescence spectroscopy. For both polymers, two different degradation behaviors were found: There is a non-linear initial reaction kinetic and a more linear behavior in later stages of the photo oxidation. In dependence on the illumination wavelength, thereaction rate may depend on the energy of incident photons or on the number of absorbed photons giving valuable information on the most probable degradation pathway. In particular for PCPDTBT, the initial reaction rate depends on absorbance pointing to the involvement of singlet oxygen in the polymer degradation. Photoluminescence spectroscopy supports this hypothesis. In contrast, in later stages a radical mechanism is proposed, , which was concluded from a clear increase of the reaction rate at higher photon energies in UV region.