Highly selective and sensitive detection of NO2 using rGO-In2O3 structure on flexible substrate at low temperature

Abstract Reduced graphene oxide (rGO)-In 2 O 3 hybrid materials were prepared by a solvothermal reaction of an In precursor containing rGO sheets, which were coated onto flexible substrates for gas sensors. The rGO-In 2 O 3 flexible sensors showed a high and reversible response (resistance ratio = 22.3) to 500 ppb NO 2 at 150 °C and negligible cross-responses to C 2 H 5 OH, CO, NH 3 , toluene, H 2 , and HCHO. The ultrahigh response and selectivity of rGO-In 2 O 3 hybrid materials to NO 2 were attributed to the chemical affinity of rGO to NO 2 and the extension of the electron depletion layer in n -type In 2 O 3 forming a p - n junction with the p -type rGO.