Bilayer Polyaniline-WO Thin-Film Sensors Sensitive to NO.

In this work, a novel bilayer polyaniline-WO (PANI-WO) thin film on the fluorine-doped tin oxide (FTO) glass substrate was prepared by hydrothermal synthesis and chemical oxidative polymerization methods. Until now, no one has ever made attempts to use the PANI-WO composite on the FTO glass substrate to detect NO gas. The composite showed excellent sensing performance for NO detection at an operation temperature of 50 °C and a detection limit of 2 ppm. With regard to the PANI-WO hybrid, the response value for NO at 30 ppm is 60.19 and is three times higher than that for pure WO at 50 °C. Besides, the PANI-WO hybrid had excellent stability. The improvement of gas sensing was assigned to the creation of p-n heterojunctions between p-type PANI and n-type WO, larger specific surface, increase of oxygen vacancies, and a wide conduction channel provided by PANI.