Effect of very fine nanoparticle and temperature on the electric and dielectric properties of MC-PbS polymer nanocomposite films

Lead sulphide (PbS) nanoparticles with very fine particle sizes were grown within methylcellulose (MC) as a capping agent, using in-situ chemical reduction from aqueous solution, and casting technique with different PbS concentrations. The XRD analysis revealed the decreases in the degree of crystallinity of PNC upon increasing PbS nanoparticles. The electrical and dielectric properties of the prepared polymer nanocomposites (PNCs) have been characterized using electrochemical impedance spectroscopy (EIS). The EIS analysis reveals a positive correlation between AC conductivity and both frequency and temperature for all PbS concentrations. At higher frequency, this correlation was found to have characteristics of Jonscher's power law. The correlation between frequency exponents and temperature was found to indicate that the conductive mechanism follows the correlated barrier hopping model (CBH). A similar positive relationship between DC conductivity and concentration was also observed. It is found that increasing PbS concentration also increases the dielectric constant and dielectric loss. The lowering of relaxation time is observed with the PbS addition that is in correlation with the AC conductivity results.