Herein, the results of a study on the electron structure and optical properties of doped polypyrrole-co-poly(pyrrole-3-carboxylic acid) copolymers are studied. The doping process leads to an increase in the number of charge carriers in the studied copolymers. Electrical conductivity results from the hopping mechanism associated with polarons and bipolarons.

The spectroscopic, thermal, and electrical properties of polypyrrole-co-poly(pyrrole-3-carboxylic acid) doped with p-TSA (p-toluenesulfonate) and AQS (anthraquinone sulfonate) are investigated. The semiconductor-like electrical characteristics of the systems are demonstrated by the variation in electrical conductivity as a function of temperature. The properties of conductivity and dielectricity are investigated. The investigated copolymers demonstrate 3D conductivity and a constant carrier density near the Fermi energy. Polarons and bipolarons are charge carriers, as indicated by IR and Raman spectra. The number of charge carriers is increased by doping the polypyrrole-co-poly(pyrrole-3-carboxylic acid) copolymer. The molecular structure of the ionized oligomer and the doped ones is analyzed using the density functional theory (DFT) methods. The time-dependent density functional theory methods are employed to analyze the electron transitions of the copolymers under investigation.