title: Substrate steered crystallization of naphthyl end-capped oligothiophenes into nanofibers: the influence of methoxy-functionalization.
abstract: Naphthyl end-capped oligothiophenes are a class of materials well suited for high-performance organics based devices. The formation of nanofibers on muscovite mica from 2,5-bis(naphth-2-yl)thiophene (NaT), 5,5'-bis(naphth-2-yl)-2,2'-bithiophene (NaT2), and 5,5''-bis(naphth-2-yl)-2,2':5',2''-terthiophene (NaT3) as well as of the methoxy-functionalized variants MONaT, MONaT2, and MONaT3 is investigated via atomic force microscopy, X-ray diffraction, polarized fluorescence microscopy, and fluorescence spectroscopy. From polarized fluorescence microscopy spatially resolved molecular orientations are deduced revealing a profound anisotropy. Fibers from lying molecules grow along distinct substrate directions. Methoxy-functionalization substantially increases the crystallization into aligned fibers. In air Ostwald ripening is observed. The morphological variations of the aggregates result in specific optical signatures, disclosed by temperature dependent and spatially resolved fluorescence spectra.
authors: NanoSyd, Mads Clausen Institute, University of Southern Denmark, DK-6400 Sønderborg, Denmark. fbalzer@mci.sdu.dk.
authors: Frank
authors: F
authors: Balzer
authors: Manuela
authors: M
authors: Schiek
authors: Andreas
authors: A
authors: Osadnik
authors: Ivonne
authors: I
authors: Wallmann
authors: Jürgen
authors: J
authors: Parisi
authors: Horst-Günter
authors: HG
authors: Rubahn
authors: Arne
authors: A
authors: Lützen