High-Performance PANI-Based Ammonia Gas Sensor Promoted by Surface Nanostructuralization

Abstract

In the area of conductive polymer-based sensors, polyaniline (PANI) has been widely studied for NH3 gas detection and a lot of effort has been devoted to improving its sensing performance. In this work, PANI thin film was prepared by chemical oxidation polymerization and spinning coating approach. By further etching via reactive ion etching (RIE), a nanostructuralized PANI thin film was obtained. All of the morphology characterization, current-voltage (I–V) characteristics curves, and XPS analysis suggest that etching via RIE with O2 gas could not only effectively increase the sensitive area and chemical diffusion pathway but also introduce extra oxygen-containing functional groups to adsorb more NH3 molecules by hydrogen bond. The gas sensing performance of the PANI thin film sensor to NH3 was examined. When the concentration of NH3 gas increased from 3 ppm to 990 ppm, the response of pristine film-based PANI sensor increased from 1.07 to 1.48, while, the response of nanostructuralized film-based PANI sensor increased from 1.16 to 3.19. All the response, reproducibility, and selectivity to NH3 results showed that the PANI sensor of nanostructuralized thin film to NH3 was superior to the PANI sensor of pristine film. This work demonstrates a convenient and effective way that can be beneficially utilized for improving the gas sensing performance.