Optically Sintered 2D RuO₂ Nanosheets: Temperature-Controlled NO₂ Reaction

Abstract

2D Ru oxide nanosheets (NSs) with optically punched nanoholes are synthesized and integrated on a flexible heating substrate, i.e., silver nanowire (Ag NW)-embedded colorless polyimide (cPI) film, for application in wearable chemical sensors. Multiple discrete pores on the sub-5-nm scale are formed on the basal planes of Ru oxide NSs by irradiation of intense pulsed light. The chemical sensing characteristic of the porous Ru oxide NSs toward nitrogen dioxide (NO2) is investigated under controlled temperatures by applying DC voltage to the Ag NW-embedded cPI film. The improved NO2 responding and recovery kinetics are achieved using the porous Ru oxide NSs with sensitivity of 1.124% at 20 ppm at a film temperature of 80.3 degrees C. A wireless patch-type sensor module is developed to demonstrate wearable sensing of NO2 using the Ru oxide NSs on Ag NW-embedded cPI heating film. This work paved the new way for application of atomically thin and porous Ru oxide NSs in chemical sensors, which can detect hazardous species in real time.