Highly flexible room temperature NO2 sensor based on MWCNTs-WO3 nanoparticles hybrid on a PET substrate

Fabrication and evolution of a flexible nitrogen dioxide (NO2) sensor made of a multi-walled carbon nanotubes tungsten trioxide nanoparticles (MWCNTs-WO3 NPs) hybrid on a polyethylene terephthalate (PET) substrate has been studied. Hydrothermally synthesized WO3 NPs and commercial MWCNTs were mixed with the assistance of α-terpineol to obtain the viscous gel of MWCNTs-WO3 NPs hybrid. The as-synthesized hybrid was gel casted on a PET substrate to fabricate the flexible sensor device. The flexible sensor showed enhanced NO2 sensing performance at room temperature with excellent mechanical flexibility, even at a curvature angle of 90° and after bending/relaxing several times (103, 104, 106, and 108). A maximum response of 14% (5 ppm) to NO2 with a limit of detection (LOD) of 0.1 ppm and relatively better recovery time (27 min) were obtained. Along with the enhanced sensing properties, lightweight and mechanical robustness of the as-prepared MWCNTs-WO3 NPs hybrid might makes it a promising building block for a flexible NO2 sensor.