High oriented epitaxial oligomer/fullerene structures grown by hot wall epitaxy

This work focuses on single layers and bilayers of p-sexiphenyl (PSP) and C60 grown by Hot Wall Epitaxy (HWE). A detailed study of the growth process was performed on glass, ITO and mica substrates. Sexiphenyl on mica forms a highly ordered anisotropic surface structure which was not observed for the other substrates by atomic force microscopy. Consequently, sexiphenyl layers grown on mica show much higher optical anisotropy (dichroic ratios up to 14 in emission) in comparison with layers grown on glass. The crystallinity of the layers was investigated by X-ray diffraction (XRD), showing clear diffraction peaks for layers grown on mica. Bilayers show a strong quenching of the photoluminescence (PL) due to the ultrafast electron transfer to C60.