Joel R. Racchini, S. Wellinghoff, S. T. Schwab
1988
Citations
0
Influential Citations
18
Citations
Journal
Synthetic Metals
Abstract
Abstract A polycarbazole consisting mostly of 3,9 linkages has been synthesized in a DMF solution by coupling 3,6-diiodocarbazole with an activated copper catalyst. Although this polymer cannot be oxidized by I2, other acceptors such as iodine monochloride or NO+ will convert it to a p-type semiconductor with a conductivity as high as 1 ohm−1 cm−1. A unique property of the oxidized polymer complex is that it displays a maximum transmittance in the visible at 600 nm and a broad near-i.r. band at 2300 nm. In a rigorously oxygen- and water-free environment, coupling between radical cations on adjacent chains produced by NO+ oxidation takes place at the remaining iodine-substituted 6,6′ positions. The 2300 nm band disappears in favor of a band at 900 nm in the crosslinked material. The decomposition pathway for bromine or ICl-oxidized material, however, involves halogenation of the ring. The large shift of the long-wavelength absorbance of the radical cation on the 3,9-linked polymer versus that found on the carbazole monomer suggests that a significant number of adjacent carbazole units are close to planarity. This must provide a significant pathway for electronic transport.