The effects of soft lithography on P3HT nanolines

We investigate the effects of three h-PDMS stamp-based nanopatterning techniques on the extent of internal alignment of poly(3-hexylthiophene) molecules and crystallite size within the fabricated nanolines. Atomic force phase imaging, x-ray diffraction and thin-film field-effect transistor measurements help provide insight into the kinds of driving forces that promote crystallization of P3HT, which is highly desirable for possible application in various optoelectronic devices. Specifically, we verify that the effects of differing rates of solvent evaporation have a clear but limited role in promoting growth of large crystallites in both unpatterned films and nanolines, which in turn results in an isotropic distribution of chains in the edge-on or face on phase regardless of the patterning technique used or the size of the h- PDMS stamp's lines. Further studies with substrates treated with silanized monolayers are necessary in order to ascertain the possibility of induced crystallite orientation due to nano- confinement by the stamps.