Charge-Transfer Complexes of a Conjugated Oligomer with Iodine: Evidence for Polaron, Bipolaron, and Ionized Bipolaron Formation

Abstract

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.

Department(s)

Chemistry and Biochemistry

Document Type

Article

DOI

https://doi.org/10.1021/ma00184a054

Publication Date

1-1-1988

Journal Title

Macromolecules

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