Ultra-sensitive polyaniline–iron oxide nanocomposite room temperature flexible ammonia sensor†
Abstract
A novel flexible, ultra-sensitive, selective, and room temperature operable polyaniline/iron-oxide (PAni/α-Fe2O3) nanocomposite ammonia (NH3) gas sensor was developed onto a flexible polyethylene terephthalate (PET) substrate by in situ polymerization process. The observations were recorded to 100 ppm fixed level for various gases including NO2, CH3OH, C2H5OH, NH3, and H2S through monitoring the change in resistance of the developed sensor. The flexible PAni/α-Fe2O3 nanocomposite sensor demonstrated better selectivity towards NH3 (response = 39% and stability = 74%). The synergistic response of the flexible PAni/α-Fe2O3 sensor was remarkable than that of the PAni and α-Fe2O3 alone; indicating the effective improvement in the performance of PAni flexible sensor on nanocomposite process. Moreover, the flexible sensor detected NH3 at low concentration (5 ppm) with a fast response (27 s) and very short recovery time (46 s). Further, PAni/α-Fe2O3 flexible sensor films were characterized by X-ray diffraction, field-emission scanning electron microscopy, UV-visible and Raman spectroscopy, Fourier transform infrared and X-ray photoelectron for structural analysis, morphological evolution, optical and surface related studies.