Thin film transistors gas sensors based on poly(3-hexylthiophene)/Zinc oxide-nanorods composite film for nitrogen dioxide detection

A new approach was proposed to evaluate the performance of organic thin film transistors (OTFTs) gas sensors. Back-gated OTFTs gas sensors with poly (3-hexylthiophene) (P3HT)/Zinc oxide (ZnO) nanorods composite film as the active layers and gas sensing layers were prepared for nitrogen dioxide (NO2) detection. Electrical parameters of OTFTs based on pure P3HT film and P3HT/ZnO-nanorods composite film were calculated and analyzed. Response characteristics of gas sensors to NO2 were studied. It can be found that responses of OTFTs gas sensors were inaccurate according to conventional definition. The slope of fitting line (ΔI versus log t) was proposed as a new method to evaluation gas properties of OTFTs sensors. The calculate results illustrated that the sensitivity can be increased 40.2% due to appropriate amount of ZnO-nanorods doping.