Edge-exposed WS2 on 1D nanostructures for highly selective NO2 sensor at room temperature

Abstract

One of the well-known pathways toward low power consuming chemoresistive gas sensors is the utilization of 2-dimensional materials. Especially, transition metal dichalcogenides (TMDs), which are usually atomically thin semiconductors, have a notable characteristic of their highly reactive edge sites. The edge sites of TMDs having high d-orbital electron density can serve as highly favorable chemically active sites for direct interaction with target gas molecules. In this study, WS2 was synthesized on highly porous SiO2 nanorods template to have numerous edge-exposed WS2 flakes in a limited active area taking advantage of 1-dimensional nanostructures with extremely high surface-to-volume ratio. The fabricated WS2 on 1D nanostructures exhibited a gas response of 151.2 % toward 5 ppm NO2, which has not been reported in performance-wise at room temperature to the best of the author's knowledge. Density functional theory calculations theoretically supported the highly sensitive and selective NO2 detection with a theoretical detection limit of 13.726 ppb.