Substrate steered crystallization of naphthyl end-capped oligothiophenes into nanofibers: the influence of methoxy-functionalization.

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.