Proton-irradiation on graphene-SnO2 hybrid nanocomposites to boost NO2 gas sensing properties

Abstract

Promising role of high-energy proton-irradiation (2 MeV) on graphene-SnO2 hybrid nanocomposites for NO2 sensing were demonstrated. We synthesized hybrid nanocomposites by using SnO2 nanoparticles and graphene flakes, being obtained from expandable graphite. NO2 gas sensing evaluations, with doses of 1 × 1012, 1 × 1013, and 1 × 1014 ions/cm2, displayed that the sensing device irradiated with a dose of 1 × 1013 ions/cm2 exhibited the highest performance at 200 °C. Generation of structural defects and graphene-SnO2 heterojunctions were accounted for sensing enhancement. Calculations in regard to density functional theory revealed that the presence of defects enhanced the NO2 sensing of the optimized sensor. Besides considering defects in the graphene, we calculated the generation of SnO2-related defects, indirectly affecting the sensing characteristics.