Spectroscopic studies of conducting polymers

Electronic and vibrational spectra of poly(p-phenylenevinylene) doped with donors or acceptors have been studied, together with the spectra obtained for the radical ions and divalent ions of its oligomers. The electronic absorption spectra of doped poly(p-phenylenevinylene) in the region from visible infrared show two bands for the H₂SO₄-doped species and one very broad band for the Na-doped species. On the basis of the analyses of resonance Raman spectra the two electronic absorption bands of the H₂SO₄-doped species are attributed to a polaron-lattice structure, whereas the broad band of the Na-doped species is attributed to overlapping absorptions associated with localized electronic levels of polarons and bipolarons. A Pauli spin susceptibility of the H₂SO₄-doped species is explained by the polaron-lattice structure.