Three-dimensional graphene network-based chemical sensors on paper substrate

We report on flexible three-dimensional (3-D) graphene network-based chemical sensors on paper substrate. Chemical-vapordeposited 3-D graphene foam network was transferred to a flexible, cheap, and environment-friendly paper substrate, followed by establishing two electrodes using Ag pastes. Conductivity of our 3-D graphene foam decreased with an increase in tensile strain. When either compressive (-0.5%) or tensile (+0.5%) strain was applied with the introduction of NO₂ gas, our 3-D graphene foam-based chemical sensors on a paper substrate were very reliable, with sensitivity up to 13.5-16.7% (200 ppm) and 22.6-23.4% (800 ppm), respectively. After each experiment, our chemical sensors were refreshed by UV treatment in a vacuum condition, which allowed us to achieve the lowest baseline by accelerating the desorption process. Our flexible 3-D graphene network-based NO₂ sensors on a paper substrate were very robust and sensitive under various tensile and compressive strain conditions.