Development of solution-processable high performance organic semiconductors for field effect transistors.

摘要

Conjugated polymers are potential active components in organic field-effect transistors (OFETs) and have received considerable attention due to their promise of high efficiency, low-cost, and mechanically flexible fabrication. This thesis describes the development of novel conjugated polymers for a high performance OFET application and the morphology and molecular packing effect on charge transport properties.;We have developed highly disordered N-alkyl dithieno[3,2-b:2',3'-d]pyrrole (DTP) and thiophene based copolymers with high charge carrier mobilities. Due to the comparatively high level of highest occupied molecular orbital, these polymers are readily oxided in air. To address this problem, we further developed environmentally stable, low temperature, solution processable DTP and bithiazole-based copolymers with reproducible high charge carrier mobilities. The morphology study revealed that unlike most conjugated polymers that have high charge carrier mobilities, these polymers are highly isotropic and have "amorphous" like microstructures. To expand the toolbox of regioregular poly(3-hexylthiophenes)(rr-P3HT), we designed and synthesized diblock copolymers composed of P3HT as rod block and the fluorinated methacrylate as coil block. These blockpolymers not only showed high hydrophobicity in thin films but also exhibited charge carrier mobility as high as P3HT homopolymer.