Energy transfer in highly oriented permethyl-dodecasilane and -octadecasilane films

Heterostructured films of permethyl-dodecasilane (DM12) and permethyl-octadecasilane (DM18) were prepared on silicon and fused quartz plates under ultrahigh vacuum conditions and the films were characterized by optical absorption and photoluminescence spectroscopy, and atomic force microscopy. The molecules were found to form highly oriented films in a layer-by-layer growth mode with their molecular chains perpendicular to the substrate surface. Moreover, it was found on the basis of optical measurement that the energy transfer progressed effectively from the optically excited state of DM12 generated by the σ–σ* one-electron transition to that of DM18 through the interface between the layers.