A simple method to recover the graphene-based chemi-resistor signal

Abstract. We present the development of a simple and fast method for restoring exhaust graphene-based chemi-resistors used for NO₂ detection. Repeatedly exposing the devices to gases or to air for more than 2 days, an overall worsening of the sensing signal is observed; we hypothesized that the poisoning effect in both cases is caused by the exposure to NO₂. Starting from this hypothesis and from the observation that NO₂ is soluble in water, we performed a recovery method consisting in the dipping of exhaust devices into ultrapure water at 100 °C for 60 s. The device performances are compared with those obtained after the restoration is achieved using the typical annealing under vacuum method.