Ammonia sensing characteristics of an ITO-V2O5 based chemoresistive dual-type gas sensors (CDGS) decorated with platinum nanoparticles

A new chemoresistive dual-type gas sensors (CDGS) has been produced and reported. The studied CDGS contains an indium tin oxide (ITO) thin layer, a vanadium (V2O5) thin layer, and platinum (Pt) nanoparticles (NPs) on a chip. The n- and p-type ammonia (NH3) sensing behaviors of the studied Pt NP/ ITO-V2O5 CDGS were systematically investigated. Initially, a high-resolution scanning electron microscopy (HRSEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) were employed to investigate the intrinsic properties. In experiments, significantly different current-voltage (I-V) curves of Pt NP/ ITO (Sensor A) and Pt NP/ V2O5 (Sensor B) were obtained in NH3-contained ambiences. The sensing response SR values for Sensors A and B are 7.54 and 1.14, respectively, under 1000 ppm NH3/air gas at 275°C. The various transient current-time (I-t) curves, under 1, 10, 100, and 1000 ppm NH3 /air gas at 275°C, for Sensors A and B were clearly observed. Moreover, both Sensors A and B demonstrated good selectivity toward NH3 gas. Thus, the presented Pt NP/ ITO-V2O5 CDGS provides the prominent potentiality and flexibility for NH3 gas detecting application.