Properties and application for electronics of poly(isomanaphthene)

Summary form only given. Poly(isothianaphthene), PITN, in the undoped state has the smallest bandgap of about 1.0 eV in the family of conjugated polymers. PITN was found to be transparent and colorless in the doped conducting state. This fact indicates that transparent conducting films can be prepared with even organic conducting polymers and low temperature processing is possible. For practical application of conducting polymers, it is desirable that the conducting polymers can be doped by both acceptor (p-type) and donor (n-type) in a reversible manner. However, a study of n-type doping is hardly ever carried out because of greater difficulties compared to p-type doping. It is also interesting from practical viewpoints whether n-type doping is possible in PITN or not. Kobayashi etal. have reported that n-type doping in PITN was very difficult. This article is concerned with the fundamental electrochemical properties of n-type doped PITN. That is, the electrochemical and optical properties of PITN during electrochemical doping have been investigated by cyclic voltammetry and optical absorption spectrum measurements. PITN can be reversibly n- and p-type doped without decomposition of the material. This polymer, PITN, with these two reversible and stable redox states of different colors is a potential candidate for electrochromic displays. The existence of a residual charge (positive or negative) depending on the electrochemical cycle is pointed out and conditions to obtain the more or less full neutralization of this residual charge are described. Further, a reading-writing device using a residual charge which remain PITN after the dedoping has also been proposed.