Orientation of regioregular poly(3-hexylthiophene) by directional solidification: A simple method to reveal the semicrystalline structure of a conjugated polymer

Highly oriented and crystalline regioregular poly(3-hexylthiophene) (P3HT) films have been obtained by directional solidification. Oriented P3HT crystallizes from a solution in 1,3,5-trichlorobenzene, which plays the dual role of solvent and orienting substrate. Periodic alternation of crystalline lamellae separated by amorphous zones, the typical fingerprint of the semicrystalline structure of P3HT, are observed (see figure).