Electronic Charge Transport Phenomenon in Polypyrrole Thin Films

The present study emphasizes on growth of polypyrrole (PPy) thin films by modified chemical bath deposition method on glass substrate at room temperature with the intension to study as gas sensing materials and electronic charge transfer phenomenon involved therein. These as deposited thin films are characterized for optoelectronic, physicochemical and ammonia gas sensing behaviour considering charge transport process. The structural analysis carried from Fourier transform infrared radiation (FTIR) represents deep at 810.10 cm⁻¹, 887.26 cm⁻¹ attributed to C-H bond while 1041.56, 1712.79 cm⁻¹ infers to C-H bond N-C stretch bending. The characteristic peaks at 1519.91 cm⁻¹ and 1550.77 cm⁻¹ correspond to the C=C stretching. The X-ray diffraction (XRD) pattern obtained shows amorphous nature of the PPy with presence of peak corresponding to glass substrate. Surface morphology as observed from the scanning electron microscope (SEM) shows granular structured grain distribution over the substrate surface with higher porosity with interlinked granules. Peaks at 328 and 420 in UV-Vis absorbance spectrum revealed bond to bond transition with exciton induced charge transfer, the energy band gap calculated from the extra plotting of UV-Vis data is 2.8 eV which corresponds for exciton induced charge transformation. The electrical characteristics confirms ohmic behavior of the samples confirming grain induced charge mobility and transportation.