Energy band structure and electronic transport properties of chlorine-doped polyaniline from ab initio calculations

The electronic properties of polyaniline are presented for each state of oxidation/reduction of this conjugated polymer, named Leucoemeraldine, Emeraldine, Protoemeraldine, Nigraniline and Pemigraniline. The calculations were carried out using the density functional theory (DFT), with the generalized gradient approximation (CGA) of Perdew-Burke-Ernzerhof (PBE), for the exchange-correlation energy, and the BFGS quasi-Newton algorithm, for the geometry optimization. The following properties were obtained: the band structure, projected density of states per atom, charge density, transmittance and electrical current. It was observed that Leucoemeraldine and Pemigraniline behave as semiconductor and narrow gap semiconductor, respectively, and Protoemeraldine, Emeraldine and Nigraniline behave as metal.