Gas detection using low-temperature reduced graphene oxide sheets

We demonstrate a high-performance gas sensor using partially reduced graphene oxide (GO) sheets obtained through low-temperature step annealing (300 degrees C at maximum) in argon flow at atmospheric pressure. The electrical conductance of GO was measured after each heating cycle to interpret the level of reduction. The thermally reduced GO showed p-type semiconducting behavior in ambient conditions and were responsive to low-concentration NO2 diluted in air at room temperature. The sensitivity is attributed to the electron transfer from the reduced GO to adsorbed NO2, which leads to enriched hole concentration and enhanced electrical conduction in the reduced GO sheet.