Synthesis and Nanostructure Control of Semiconducting Polymers

Abstract

This article describes the synthesis of hole transporting polymers containing triphenylamine (TPA) unit either in side chain or main chain for electroluminescent devices, and photorefractive applications. Radically polymerized polyacrylate having tetraphenyldiaminobiphenyl (TPD) unit showed higher drift mobility compared with conventional poly(N-vinylcarbozole) (PVK). TPA derivatives were reacted with paraformaldehyde or benzaldehyde in the presence of p-toluenesulfonic acid to yield polymers soluble in common organic solvents. Acid catalyzed Friedel-Crafts reactions between TPA derivatives and divinylbenzene were also applied to prepare the main chain polymers. TPA derivatives were oxidatively coupled to afford polymers with well-defined structure. Resulting polymer sensitized with fullerene showed much higher photoconductivity than PVK. Electron transporting polymers having oxadiazole, fluorene, or thioxanthene unit are also introduced. For the further improvement of device performance, molecular design for multifunctional and multiphased materials including block copolymers and rod-coil type polymers is described.