ELECTRONIC-PROPERTIES OF P-TYPE DOPED COPOLYMERS CONSISTING OF OLIGOTHIENYLENE AND DISILANYLENE UNITS

In association with the previous theoretical prediction on the ferroma gnetic spin correlation in p-type doped poly[disilanylene(thienylene)( n)] (PDST-n, n = 1-5), we have actually prepared these samples and exa mined their electronic properties by the combination of cyclic voltamm etry (CV), ultraviolet-visible-near-infrared (UV-vis-NIR), electron sp in resonance (ESR), and infrared (IR) spectroscopic measurements. It h as been confirmed that electrons are removed mainly from oligothienyle ne units. A spin generated by the doping was found to be localized at 3p(pi)-atomic orbitals (AOs) of sulfur atom at n = 1. For n = 2-5 a sp in was the polaronic pi-spin delocalized within an oligothienylene uni t. These natures of radical spins are in accordance with the previous theoretical study. However, the spin concentration of p-type doped pol ymers was considerably small (1 spin/ca. 400 oligothienylene units), p ossibly due to the aggregation of the oligothienylene units around the dopant and to the degradation of disilanylene units. No signs of ferr omagnetic interaction has been observed yet due to such small spin con centrations.