The effect of oxygen on the ESR linewidth in polypyrrole doped by PF 6−

Abstract

ESR linewidth ( ΔH pp ) of as-grown polypyrrole, PPy-PF 6 −, was measured as a function of temperature under both helium and oxygen atmospheres to study an effect of oxygen on the ESR linewidth. Houzé and Nechtschein reported that an interaction between the charge carriers on a polymer backborn and paramagnetic spins of the oxygen molecules could cause an additional ESR broadening that is proportional or inversely proportional to the carrier diffusion rate D ∥ in the case of storng or weak interaction, respectively. The present experimental data demonstrate that only the ESR linewidth under oxygen atmosphere are not enough, but other information is indispensable to discriminate the above two cases. On the present PPy-PF 6 − case, supplemental data on d.c. conductivity, the ESR linewidth under helium atmosphere, VSC resistance, etc. make it possible to conclude mechanism of oxygen effect.