Facile Fabrication of C 60 Fullerene Nanowhisker Gas Sensors Based on Electric-Dipole Mediated Gas Sensing

Abstract This paper presents a simple fabrication process of C 60 fullerene nanowhisker (C 60 FNW) gas sensors, and discusses a novel sensing mechanism based on dipole-induced dipole interactions between polar gas molecules and C 60 p-electron systems at room temperature. Two-electrode and FET(field-effect transistor)-based three-electrode gas sensors were fabricated, where slit-gap-type C 60 FNW-based FET gas sensors with graphite electrodes and circular-gap-type C 60 FNW-based FET gas sensors with bamboo charcoal cloth electrodes were fabricated. Seebeck effect experiments showed the C 60 FNWs synthesized using the liquid-liquid interfacial precipitation method exhibited p-type semiconducting properties, which was consistent with the measured semiconducting properties of the FET gas sensors. Polar gases like methanol demonstrated distinct sensor currents, whereas the non-polar gases, such as CCl 4 , exhibited no sensor response. An increase in electrical conductivity due to the reduction of the HOMO-LUMO gap of C 60 molecules caused by the adsorption of polar molecules, along with an increase in the adsorption probability via the dipole-induced dipole moment interactions between the polar molecules and C 60 molecules, produces a pronounced sensor response for polar gases. The FET sensors exhibited linear relationships between the source-drain voltage and source-drain current, as well as between the gate voltage and source-drain current.