Augmentation of room temperature gas sensing properties of PANI thin films by 100 keV Ar+ ion irradiation

Abstract

Polyaniline thin films were subjected to irradiation with Ar+ ions at four different concentrations: 1 × 1014, 1 × 1015, 1 × 1016, and 3 × 1016 ions/cm2, with an energy of 100 keV to improve the sensing ability. Field emission scanning electron microscope (FESEM) images revealed that the porosity as well as surface area of thin films increase significantly with the increase in fluence dose. The bandgap energy of the irradiated thin films found to decrease from 3.04 to 2.36 eV, whereas, the number of carbon atoms per cluster are found to increase from 127 to 211 atoms with increasing the Ar+ ions dose from 1x1014 to 3x1016 ions/cm2. The ratios of the areas under the curves AQ/AB are increased from 0.221 to 0.456 as the Ar+ ion fluence dose rate rose from 0 to 3 × 1016 ions/cm2. Thus, it can be assumed that the electrical conductivity of the PANI films increase with the Ar+ ion fluence dose rate via carbonaceous clustering, and the scission of polymer chains. The as-deposited PANI thin film demonstrated the lowest sensing response at approximately 33 %, while the thin film irradiated with the highest dose of 3 × 1016 ions/cm2 exhibited the highest sensing response at around 1119 % for methanol vapors at a concentration of 100 ppm.