Field-effect hole mobility of poly(3-hexylthiophene-block-3-(2-ethylhexyl)thiophene)s

The field-effect hole mobility of a series of highly regioregular all-conjugated P(3HT-b-3EHT) diblock copolymers was investigated. Although disordered segments of P3EHT were introduced, thin films of P(3HT-b-3EHT)s with 83 mol% P3HT exhibited field-effect hole mobilities up to 0.14 cm2 V−1 s−1 without any thermal treatment. In contrast, the corresponding random copolymers P(3HT-ran-3EHT)s showed a monotonic decrease in mobility upon introduction of 3EHT monomer units, owing to the decrease in polymer crystallinity. Absorption spectra of the films suggest the formation of improved structural order induced by the P3EHT block, which contributed to improved carrier transport properties in P(3HT-b-3EHT)s.