Vertically aligned PANI nanorod arrays grown on graphene oxide nanosheets for a high-performance NH3 gas sensor

In this paper, vertically aligned PANI nanorod arrays were successfully prepared on GO nanosheets at low temperature via a dilute polymerization method, in which the GO nanosheets with abundant hydrophilic groups were employed to support the heterogeneous growth of uniformly-distributed PANI nanorod arrays. The acquired nanocomposite was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). NH3 sensing performances of the as-prepared nanocomposite were carefully examined. With the help of the enhanced synergistic effect derived from the large number of p-n heterojunctions in the deliberately-designed microstructure, the device exhibited an enhanced response to NH3 vapor (14.63 at 50 ppm), wide dynamic range (1-6400 ppm), and fast response and recovery processes, in comparison to pure PANI nanofibers. The impact of the drop-coating amount of the sensing nanocomposite on the sensing performances was also investigated to find out the suitable amount for fabricating a high-performance ammonia sensor. Herein, the superior performances of the proposed well-organized microstructure make it an effective nanocomposite for gas sensing applications.