Regensburg 2013 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 32: Poster: Organic Semiconductors
CPP 32.14: Poster
Wednesday, March 13, 2013, 16:30–18:30, Poster C
Morphological aspects of the exciton transport in thin films of Diindenoperylene — •Alexander Steeger1, Anna Katharina Topczak1, and Jens Pflaum1,2 — 1Experimental Physics VI, Julius Maximilian University of Würzburg, 97074 Würzburg — 2ZAE Bayern, 97074 Würzburg
The exciton diffusion length (EDL) is a key criterion for an optimized design of organic thin film devices. As a tight correlation between morphology and charge carrier as well as exciton transport properties has been evidenced in previous studies, the extension of crystalline domains has been proposed beneficial for long range exciton transport [1]. To address this point we have varied the morphology of Diindenoperylene (DIP) thin films by means of the substrate temperature (TS). X-ray diffraction analysis revealed an almost amorphous phase of DIP grown at TS = 100 K, whereas TS = 300 K and 400 K yield to long range ordered polycrystalline films of higher crystallinity with increasing TS. Photoluminescence-quenching measurements together with an advanced modeling were performed to correlate the EDL to the DIP morphology. Long range ordered DIP layers grown at TS = 300 K and 400 K show a high EDL (59 nm and 115 nm, respectively), whereas the EDL of DIP deposited at TS = 100 K is significantly smaller. This result emphasizes the importance of long range structural order to achieve superior transport properties of photo-generated electron-hole pairs. Financial support by the DFG focus program SPP 1355 is gratefully acknowledged. [1] R. R. Lunt et al., Adv. Mater 22 (2010) 1233-1236