Thermally stimulated discharging current spectra of poly(p-phenylene) polymer

The authors report a set of thermally stimulated discharging current (TSDC) spectra of undoped poly(p-phenylene) (PPP) polymer over the temperature range of 4 to 500°K. At heating rates of 2 and 3.5 °C/min, five TSDC peaks were observed at around 136, 159, 245, 290, and 343 °K, respectively. As the first stage of the TSDC study of doping effect on conducting polymers, the authors present the TSDC spectrum of a low-level FeCl₃-doped PPP polymer. It was found that doping caused a fivefold increase in the 245 °K TSDC peak whereas DC conductivity was increased by nearly 6 orders of magnitude, i.e., from 10^-14 to 10^-8 S/cm, by doping. The differential scanning calorimetry spectrum of PPP is also presented