Electrospun SnO2 nanofiber mats with thermo-compression step for gas sensing applications

Abstract

SnO2 nanofiber mats fabricated through electrospinning followed by thermo-compression and subsequent calcination steps exhibited unique morphologies facilitating efficient gas transport into the layers combined with high surface area (similar to 73.5 m(2)/g, measured by BET) and small grain size (similar to 5-15 nm), which are well suited for ultrasensitive gas detection. Single SnO2 nanofibers were found to have a belt-like structure of closely packed nanocrystallites, facilitating excellent adhesion to the substrate and good electrical contact to the electrodes. I-V measurements of single SnO2 nanofibers displayed ohmic behavior with electrical conductivity of 1.5 S/cm. Gas sensor prototypes comprising a random network of SnO2 fibers exhibited high sensitivity when exposed to NO2 at 225A degrees C and CO at 300A degrees C. A detection limit of 150 ppb NO2 at 185A degrees C was estimated by extrapolating the sensitivity results obtained on exposure to higher gas concentrations, demonstrating potential of achieving ultra-sensitive gas detection at low operating temperatures enabled by the present synthesis method.