Identification of oxidized polypyrrole on Raman spectrum

In this study, the peak shown at the higher frequency of the double peaks at about 1052 and 1083 cm-1 in surface-enhanced Raman spectroscopy (SERS) is initially assigned to be the CH in plane deformation of oxidized polypyrrole (PPy). Then, a systematic study is carried out to confirm this assignment. It is found that the conductivity of PPy is strongly related to and increases with this Raman peak intensity of oxidized PPy. Meanwhile, the normalized relative intensities of this Raman peak for various PPy films are consistent with their corresponding doping levels.