Fast response ammonia sensor based on porous thin film of polyaniline/sulfonated nickel phthalocyanine composites

Porous thin film composites of PANI/NiTSPc were deposited across the gaps of interdigitated Au electrodes (IAE) by an electrochemical polymerization method. The PANI/NiTSPc films were characterized by scanning electron microscopy (SEM) images, atomic force microscopy (AFM) images, energy dispersive spectra (EDS), Raman spectra and Fourier transform infrared (FT-IR) spectra. Ammonia (NH3) gas-sensing properties of the films prepared at optimum conditions were examined at room temperature. The observed response value (S) of the film to 100 ppm NH3 was 2.75 with a response time as short as 10 s. Furthermore, fast recovery rate, good reproducibility and acceptable long-term stability were also observed over a concentration range from 5 to 2500 ppm The outstanding sensing performance may be attributed to the porous, ultra-thin film structure and the “NH3-capture” effect of the “flickering” NiTSPc molecules. Therefore, the proposed PANI/NiTSPc nanocomposite thin film sensors are excellent potential candidates for NH3 detection.