Synthesis of polypyrrole by electrochemical polymerization using organic anion electrolytes and its application

The synthesis of polypyrrole from aqueous solutions using various organic anion electrolytes and its electric and mechanical properties and the junction characteristics of sandwich devices were investigated. As electrolytes the following anions were used: p‐toluenesulfonate (p‐TS‐), benzenesulfonate (BS‐), dodecylbenzenesulfonate (DBS‐), naphthalene‐2‐sulfonate (N‐2‐S‐) and sulfosuccinate (SS‐1); their effect on the conductivities of the polypyrroles decreases in the order DBS‐1 > p‐TS‐1 > N‐2‐S‐1 > BS‐ > SS‐. Higher conductivity and mechanical properties were obtained by drawing of films. With indium, polypyrrole forms rectification contacts, whereas ohmic contacts are formed in junction with Au or Pt. From the analysis of the current‐vs.‐voltage and capacitance‐vs.‐voltage characteristics, it is suggested that a Schottky barrier is formed at the interface between polypyrrole and indium.