Regensburg 2016 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 18: Molecular Electronics and Photonics
CPP 18.6: Vortrag
Dienstag, 8. März 2016, 10:45–11:00, H42
Electronic Properties of Optically Switchable Photochromic Diarylethene Molecules at Interface with Organic Semiconductors — •Qiankun Wang1, Johannes Fisch1, Björn Kobin2, Stefan Hecht2, and Norbert Koch1 — 1Institut für Physik & IRIS Adlershof, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 6, 12489 Berlin, Germany — 2Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489 Berlin, Germany
Photochromic organic molecules have attracted increasing interest for the development of low-cost multifunctional devices. Diarylethene (DAE) molecules, which are among the most interesting photochromes, show promising application potentials due to their high fatigue resistance and thermal bistability, and the interface energetics of DAE-based (bulk and planar) heterojunction is of high importance for understanding the effects on charge transport in photoswitchable devices. Here, the valence electronic structure upon switching of a photochromic diarylethene derivative, 1,2-bis (2-methyl-5-p-tolylthiophen-3-yl) cyclopent- 1-ene (DAE1) was measured by ultraviolet photoelectron spectroscopy. Switching between open and closed forms was followed in situ upon appropriate illumination with ultraviolet and visible light, respectively. The energy level alignment at interfaces between DAE1 and organic hole (electron) transport materials was observed to be affected by the photoisomerization process, which resulted in different charge transport energy barriers for holes (electrons) before and after light irradiation. Our experimental findings provide a rationale for photo-control of charge transport in organic electronic devices.