Molecular orientation and anisotropic carrier mobility in poorly soluble polythiophene thin films

Oriented thin films of a poorly soluble polythiophene, poly[benzo[1,2-d:4,5-d′]bisthiazole-2,6-diyl(3′,4,4″,4″′-tetradodecyl[2,2′:5′,2″:5″,2″′-quaterthiophene]-5,5″′-diyl)], were fabricated using the friction-transfer technique. The detail of the film structure was investigated using polarized UV-vis spectroscopy, transmission electron microscopy, and grazing-incidence x-ray diffraction observations. The friction-transfer technique enables control of the anisotropic carrier transport according to the face-on and/or edge-on molecular orientations in films with one-directionally aligned polymer backbones.