Copolythiophenes with Hydrophilic and Hydrophobic Side Chains: Synthesis, Characterization, and Performance in Organic Field Effect Transistors

• Published in: Macromolecular chemistry and physics 2012-09, Vol.213 (18), p.1970-1978
• Main Authors: Bilkay, Taybet, Schulze, Kerstin, Egorov-Brening, Tatjana, Bohn, Andreas, Janietz, Silvia
• Format: Article
• Language: English
• Subjects: air stable; Applied sciences; conjugated polymers; Electronics; Exact sciences and technology; organic field effect transistors; Organic polymers; Physicochemistry of polymers; Polymers with particular properties; polythiophene; Preparation, kinetics, thermodynamics, mechanism and catalysts; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Transistors
• ISSN: 1022-1352; 1521-3935
• DOI: 10.1002/macp.201200267

Statistical copolymers of regioregular polythiophene with hydrophobic hexyl side chains (P3HT) and hydrophilic 3,6‐dioxaheptyl side chains (P3DOHT) are synthesized by the GRIM method. A comparable study on the different polymers has been accomplished regarding solubility, thin film structure, and performance in organic field effect transistors (OFETs). DSC and XRD measurements are done to investigate the crystallinity of the copolymers. The novel functionalized fully π‐conjugated copolymers P(3HT‐co‐3DOHT) with feed molar ratios of 1:1, 2:1, and 1:2 show hole mobilities in the range of 10−2 cm2 V−1 s−1. Using poly(methyl methacrylate) as the dielectric layer in a top gate device architecture leads to air stable transistors without significant losses in the OFET performance over several months. Synthesis of different statistical copolymers P(3HT‐co‐3DOHT) and a diblock copolymer P(3HT‐b‐3DOHT) for application in OFETs is described. In comparison to the homopolymer P3HT, transistors based on these novel materials including hydrophilic side chains and PMMA as the dielectric showed high air stability over several months.