Charge Carrier Dynamics of Electrochemically Synthesized Poly (Aniline Co-Pyrrole) Nanospheres Based Sulfur Dioxide Chemiresistor
Vishal Chaudhary
Abstract
Poly(aniline co – pyrrole) (PAP) nanospheres (diameter ~50 nm) have been synthesized by using cost-effective electrochemical oxidation of monomers, i.e., aniline, and pyrrole (1:1 ratio), and evaluated as sulfur dioxide chemiresistor. PAP chemiresistor exhibited an improved sensing response (6.1%) toward a low concentration of sulfur dioxide (5 parts per million) compared to its precursor-based chemiresistors at room temperature. It is attributed to the remarkable characteristics of PAP, such as higher surface-to-volume ratio, larger effective surface area, higher branching, and lower conductivity value. Furthermore, the cause of low conductivity was evaluated using low-temperature direct current charge transport studies. The dependence of activation energy on temperature discarded the probability of band conduction mechanism in the synthesized PAP nanospheres. PAP nanospheres were found to possess 3-Dimensional VRH conduction of charge carriers. The low conductivity of PAP nanospheres is further explained by evaluating Mott’s parameters, i.e., characteristic temperature, hopping radius, hopping energy, and density of states.