In connection with the use of conducting conjugated polymers in organic electronics, the study of their properties has currently become a topical issue. Using a highly sensitive method of optically detected electron paramagnetic resonance of spin-correlated ion-radical pairs, we studied the EPR spectra of ion-radical states formed as a result of the capture of positive and negative charges by molecules of substituted polyfluorenes in non-polar solutions. These charge states, which can be considered polarons, do not propagate along the entire polymer chain, but occupy regions of a certain length. In the present work, the polaron size is determined under conditions where the structure of the ionized polymer chain is minimally distorted by the environment. The sizes of both positively and negatively charged polarons significantly exceed those previously observed in polar solutions and films of conjugated polymers and are approximately 18 monomer units (≈15 nm) for cyclohexane solutions of poly(9,9-dioctyl-fluorenyl-2,7-diyl). Thus, solid-state device designers have an untapped resource for increasing polaron lengths to sizes determined by the properties of individual molecules.
O.A. ANISIMOV (Thu,) studied this question.