Flexible Paper-Based Room-Temperature Acetone Sensors with Ultrafast Regeneration

Paper-based lightweight, degradable, low-cost, and eco-friendly substrates are extensively used in wearable biosensor applications, albeit to a lesser extent in sensing acetone and other gas-phase analytes. Generally, rigid substrates with heaters have been employed to develop acetone sensors due to the high operating/recovery temperature (typically above 200 °C), limiting the use of papers as substrates in such sensing applications. In this work, we proposed fabricating the paper-based, room-temperature-operatable acetone sensor using ZnO-polyaniline-based acetone-sensing inks by a facile fabrication method. The fabricated paper-based electrodes showed good electrical conductivity (80 S/m) and mechanical stability (∼1000 bending cycles). The acetone sensors showed a sensitivity of 0.02/100 ppm and 0.6/10 μL with an ultrafast response (4 s) and recovery time (15 s) at room temperature. The sensors delivered a broad sensitivity over a physiological range of 260 to >1000 ppm with R2 > 0.98 under atmospheric conditions. Further, the role of the surface, interfacial, microstructure, electrical, and electromechanical properties of the paper-based sensor devices has been correlated with the sensitivity and room-temperature recovery observed in our system. These versatile, green, flexible electronic devices would be ideal for low-cost, highly regenerative, room-/low-temperature-operable wearable sensor applications.