Carrier Dynamics in Conducting Polymers: Case of PF6 Doped Polypyrrole

The carrier dynamics in $PF-^{6}$ doped polypyrrole has been probed by dielectric spectroscopy (from $10-^{4 }$to 4 eV), down to 4.2 K. The phase-sensitive sub-THz data have assisted to resolve the discrepancies in Kramers-Kronig analysis in earlier studies. Even in metallic samples, just 1% of the carriers are delocalized, at 300 K; the fraction drops down considerably as a function of disorder, carrier density, and temperature. This subtle metallic feature and the anomalies in carrier dynamics are attributed to coherent and incoherent transport between short conjugated segments.