Synthesis of silicon‐bridged polythiophene derivatives and their applications to EL device materials

Palladium‐catalyzed oxidative homo‐coupling of 2,6‐bis(tributylstannyl)dithienosiloles with CuCl 2 afforded poly(dithienosilole‐2,6‐diyl)s as novel polythiophene derivatives with intra‐chain silicon bridges, which exhibited red‐shifted UV absorption maxima by about 100 nm from those of the corresponding silole‐free polythiophenes. Alternate copolymers also were prepared by palladium‐catalyzed cross‐coupling reactions of 2,6‐dibromodithienosiloles with distannylthiophene or bithophene. These polymer films were applied to single and double‐layered organic electroluminescence devices. It was found that some of the resulting polymers exhibited electroluminescence properties and emitted red light in EL devices with the structure of ITO/polymer/Mg‐Ag. Introducing an electron‐transporting Alq3 layer between the polymer film and the Mg‐Ag cathode led to a remarkable improvement in the devices performance. An application of the copolymer to a field effect transistor was also studied. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4588–4596, 2007