Dresden 2017 – wissenschaftliches Programm
CPP 41.10: Vortrag
Mittwoch, 22. März 2017, 17:45–18:00, ZEU 260
Watching Paint Dry: The Impact of Diiodooctane on the Kinetics of Aggregate Formation in Thin Films of Poly(3-hexylthiophene) — •Markus Reichenberger1, Sebastian Baderschneider2, Daniel Kroh1, Steffen Grauf1, Juergen Koehler2,3, Richard Hildner2, and Anna Koehler1,3 — 1Experimental Physics II, University of Bayreuth, 95440 Bayreuth, Germany — 2Experimental Physics IV, University of Bayreuth, 95440 Bayreuth, Germany — 3Bayreuth Institute of Macromolecular Research (BIMF), University of Bayreuth, 95440 Bayreuth, Germany
We have investigated how the addition of 1,8-diiodooctane (DIO) alters the formation of disordered and ordered phases in a film of poly(3-hexylthiophene-2,5-diyl) (P3HT). By combining in situ time-resolved absorption spectroscopy with 60 ms time resolution, optical and transmission electron microscopy and spatially resolved photoluminescence spectroscopy, we show that, in addition to the excitonic coupling, the film formation process during spin-coating as well as the subsequent long-time film drying process differ significantly when DIO is added to a solution of P3HT. During spin-coating, the addition of DIO reduces the actual time for transformation from disordered to ordered phase, even though it increases the time until the disorder-order transition sets in. In place of a solidification front, we observe an all-over solidification throughout the entire film. The phase separation between nonaggregated and aggregated phase increases when using DIO, with compositional variation in the content of aggregated phase on a micrometer scale.