Comparison of electronic transport properties of soluble polypyrrole and soluble polyaniline doped with dodecylbenzene-sulfonic acid

The temperature dependences of the conductivity of soluble polypyrrole (PPy) and soluble polyaniline (PANI) films doped with dodecylbenzene-sulfonic acid (DBSA) have been studied. The room temperature conductivities of samples were 1–8 and 95–100 S/cm, with resistivity ratio ρr=ρ(20 K)/ρ(300 K)∼104 and ρr=ρ(1.4 K)/ρ(300 K)∼32 for PPy-DBSA and PANI-DBSA, respectively. At low temperatures, the temperature dependence follows the σ(T)=σ0exp[−(T0/T)m] law, which has been explained within the framework of granular metals model (m=0.5) for PPy-DBSA and Mottʹs variable range hopping model (m=0.25) for PANI-DBSA. The magnetoresistance of PANI-DBSA is positive and follows H2 and H1/3 dependencies at low and high magnetic fields, respectively; the magnitude of the magnetoresistance is strongly temperature dependent.