Design and preparation of the WO3 hollow spheres@ PANI conducting films for room temperature flexible NH3 sensing device

Abstract The development of room temperature NH 3 sensors with flexible substrate can fulfill the future demands of high NH 3 sensing performance under the premise of lower energy consumption and safety circumstance in wearable electronics field. The polyaniline and a serious of WO 3 hollow spheres@ polyaniline hybrid were successfully synthesized via a combined route of simple hydrothermal method and in-situ chemical oxidative polymerization. The room temperature NH 3 sensors were fabricated by assembling WO 3 hollow spheres@ polyaniline hybrid on flexible polyethylene terephthalate (PET) films. The NH 3 sensing properties of the fabricated devices demonstrated that the device utilizing 10 mol% WO 3 hollow spheres@ polyaniline (PAWHs 10) hybrid exhibited the best sensing performance to 100 ppm NH 3 (response value at 25) at 20 °C. Moreover, the PAWHs10 hybrid sensor also achieved excellent NH 3 selectivity, ppb-level detection limit (1.67–500 ppb NH 3 ), and good response/recovery rates (136 s/130 s) at 20 °C. The enhanced sensing performance of incorporation of polyaniline and WO 3 hollow spheres was mainly attributed to the hollow structure of WO 3 and the formation of p-n heterojunction between PANI and WO 3 hollow spheres.