Enhanced AC conductivity and dielectric relaxation properties of polypyrrole nanoparticles irradiated with Ni12+ swift heavy ions

In this paper, we report the 160 MeV Ni12+ swift heavy ions (SHIs) irradiation effects on AC conductivity and dielectric relaxation properties of polypyrrole (PPy) nanoparticles in the frequency range of 42 Hz-5 MHz. Four ion fluences of 5 × 1010, 1 × 1011, 5 × 1011 and 1 × 1012 ions/cm2 have been used for the irradiation purpose. Transport properties in the pristine and irradiated PPy nanoparticles have been investigated with permittivity and modulus formalisms to study the polarization effects and conductivity relaxation. With increasing ion fluence, the relaxation peak in imaginary modulus (M″) plots shifts toward high frequency suggesting long range motion of the charge carriers. The AC conductivity studies suggest correlated barrier hopping as the dominant transport mechanism. The hopping distance (Rω) of the charge carriers decreases with increasing the ion fluence. Binding energy (Wm) calculations depict that polarons are the dominant charge carriers.