Relaxation and charge transport phenomena in polyaniline nanofibers: Swift heavy ion irradiation effects

• Published in: Journal of non-crystalline solids Vol. 358; no. 22; pp. 2990 - 2998
• Main Authors: Banerjee, Somik, Kumar, A.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 01.11.2012; Elsevier
• Subjects: ac conductivity; Condensed matter: structure, mechanical and thermal properties; Correlated barrier hopping; Cross-disciplinary physics: materials science; rheology; Dielectric spectroscopy; Diffusion in nanoscale solids; Diffusion in solids; Exact sciences and technology; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Materials science; Nanoscale materials and structures: fabrication and characterization; Physics; Polyaniline; Quantum wires; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Swift heavy ions; Transport properties of condensed matter (nonelectronic); Swift heavy ions; ac conductivity; Dielectric spectroscopy; Polyaniline; Correlated barrier hopping; Radiation effects; Electrical conductivity; Heavy ions; Charge carriers; Doping; Polymerization; Nanofiber; Charge transport; Relaxation time; Dielectric relaxation; Charge carrier trapping; Ion irradiation; Transport processes; Activation energy; Power law; Nanostructured materials; Polarons
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2012.07.033

Relaxation and charge transport mechanisms in hydrochloric acid (HCl) doped polyaniline (PAni) nanofibers synthesized using interfacial polymerization technique and the swift heavy ion irradiation effects have been investigated by dielectric relaxation spectroscopy. Non-Debye type relaxation with a distribution of relaxation times observed in PAni nanofibers is dominated by hopping of trapped charges. Swift heavy ion irradiation induces a benzenoid to quinoid transition in PAni nanofibers. Dynamic processes occurring at different frequencies in PAni nanofibers exhibit the same activation energy which reveals an enhanced coupling among the localized short range dipolar motions. The increase in conductivity relaxation time upon irradiation indicates an increase in the carrier hopping length thereby impeding charge transport. The ac conductivity of the pristine and irradiated PAni nanofibers has been found to obey the universal power law of frequency. Although charge transport in both the pristine and irradiated PAni nanofibers follows the correlated barrier hopping (CBH) model with polarons as major charge carriers, significant decrease in conductivity has been observed upon irradiation. ► Non-Debye type relaxation in PAni nanofibers ► Relaxation mechanism dominated by hopping of trapped charges ► Benzenoid to quinoid transition in PAni nanofibers upon SHI irradiation ► Increase in relaxation times upon SHI irradiation ► Charge transport mechanism follows correlated barrier hopping (CBH) model.