Theoretical studies on the structural changes of conjugated conductive polymers in the heavily-doped regime

• Published in: Synthetic metals 1989-08, Vol.31 (2), p.181-190
• Main Authors: Tanaka, Kazuyoshi, Okada, Mayumi, Koike, Tsuneaki, Yamabe, Tokio
• Format: Article
• Language: English
• Subjects: Applied sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Properties and characterization
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/0379-6779(89)90813-8

Structural changes of simple π-conjugated organic polymers such as trans-polyacetylene, polyyne and polydiacetylene in their cationic states have been studied in detail with a view to examining the carbon-carbon bond deformation in their heavily-doped regime. It has been theoretically bound for the first time that although the well-known bond alternations and band gaps in these polymers tend to reduce in this regime, they never actually vanish within realistic doping levels. These findings agree well with the optical observations reported with respect to heavily-doped polyacetylenes. In this sense, the ‘counter Peierls’ transition, the concept of which was employed in a preliminary study, is unlikely to be completed and, hence, this terminology should be used with certain reservations.