Alcohol gas sensors capable of wireless detection using In₂O₃/Pt nanoparticles and Ag nanowires

An unconventional method is developed to fabricate flexible and transparent sensors for real-time, wireless sensing of alcohol vapors using hybrid nanostructures of indium oxide and Pt nanoparticles (as an active channel) with random networks of metal nanowires (as electrodes and antennas). The hybrid structures of indium oxide and Pt nanoparticles present high response and selectivity for ethanol vapor sensing with detecting the blood alcohol concentration range corresponding to the license suspension or revocation in the Road Traffic Act of many countries (blood alcohol concentration 200 ppm). The integration of a Bluetooth system or an inductive antenna enables wireless operations of the alcohol sensor using smartphones for applications as wearable and hands-free devices with flexible, transparent film geometries. Furthermore, these sensor systems exhibit outstanding thermal reliabilities for their stable operations over wide temperature ranges between −40 °C and 125 °C, which can extend their practical use for automobile electronics. Such devices can be transferable onto diverse nonplanar surfaces including steering wheels and curved glasses of phones, which suggests substantial promise for their applications in next-generation automobile or wearable electronics.