HIGH MOBILITIES FOR BLOCK COPOLYMERS OF REGIOREGULAR POLY(3-HEXYLTHIOPHENE)

摘要

Regioregular poly(3-hexylthiophene) (RR-P3HT) have received considerable attention for use in organic field effect transistors due to their high mobility, solution processability and easy of synthesis. Not much attention has been given to a new class of materials that we have developed: block copolymers of RR-P3HT, where RR-P3HT is bound to a second polymer segment. By varying the physical properties of the non-conjugated segment, it is possible to fine-tune the physical and electrical properties of the copolymer for various device applications. Block copolymers are also often used to induce self- assembly. So far, the self-assembly of block copolymers or RR-P3HT seems to be governed by the strong π-stacking force of RR-P3HT, forming nanoribbons. We have previously shown that block copolymers of RR-P3HT have relatively high conductivities, despite the presence of the insulating polymer block. In this report, we explore the field-effect mobility of a series of diblock copolymer where the first block is RR-P3HT and the second block is poly(methyl acrylate) (PMA). PMA is a soft polymer with a low T_g of 5°C. Here, the molecular weight of the RR-P3HT segment was kept constant, while the molecular weight of the second segment was varied. Preliminary mobility measurements show that diblock copolymers of RR-P3HT can have mobilities nearly as high as that of the homopolymer RR-P3HT.