Enhanced NO2 gas-sensing performance at room temperature using exfoliated MoS2 nanosheets

Abstract

Features such as surface-to-volume ratio, sensitive surface, and bandgap vary with the number of material layers of semiconductor two-dimensional transition metal dichalcogenides with superior responsivity at room temperature (RT) and their possible application as flexible electronic devices. Herein, a significant enhancement of NO2 gas sensing properties of few-layered MoS2 nanosheets exfoliated from bulk MoS2 through a simple sonication probe was reported. The gas responses of the sensor based on the exfoliated MoS2 nanosheets to 0.5–5 ppm NO2 at RT were as high as 5.3–8 times. At RT, the humidity effect to the performance of the exfoliated MoS2 sensor was insignificant. The exfoliated MoS2 sensor also exhibited an ultra-low detection limit of 27 ppb, excellent selectivity, and reliable long-term stability within 8 weeks, which are crucial for future application of the sensor in practical devices. The NO2 sensing mechanism of the exfoliated MoS2 nanosheets was discussed in detail.