Charge-Transfer Complexes of a Conjugated Oligomer with Iodine: Evidence for Polaron, Bipolaron, and Ionized Bipolaron Formation
This paper describes the results ofelectron spin resonance experiments on the charge-transfer complexes that are formed when the conjugated oligomer poly(4,4'-dibromobiphenyl-co-1,4-diethynylbenzene) is dopedwith iodine. The dependence of the spin susceptibility on the iodine content is interpreted in terms of the formation of polarons (radical cations with S = 1/2), bipolarons (cations with S = 0), and ionized bipolarons (radical trications with S = 1/2). The dependences of the effective g value and the line-shape parameters on the iodine content are explained in terms of an equilibria scheme involving different stoichiometric forms of these two types of radical cations. A dependence of the line-shape parameters on the radical concentration is also identified and is explained in terms of intermolecular spin-spin interactions.
Chemistry and Biochemistry
Brown, I. M., and J. M. Wilbur. "Charge-transfer complexes of a conjugated oligomer with iodine: evidence for polaron, bipolaron, and ionized bipolaron formation." Macromolecules 21, no. 6 (1988): 1859-1863.