Effect of fluorine doping on the NO2-sensing properties of MoS2 nanoflowers

Abstract

The somewhat slow recovery kinetics of NO2 sensing at low temperatures are still challenging to overcome. To enhance the gas sensing property, fluorine is doped to MoS2 nanoflowers by facile hydrothermal method. Extensive characterization data demonstrate that F was effectively incorporated into the MoS2 nanoflowers, and that the microstructure of the MoS2 nanoflowers did not change upon F doping. The two MoS2 doped with varying concentrations of fluorine were tested for their sensing property to NO2 gas. Both of them show good repeatability and stability. A smaller recovery time was seen in the F-MoS2-1 sample with a little amount of F loading, which was three times quicker than that of pure MoS2. The key reason for the quicker recovery time of this material was found to be the fluorine ions that had been adsorbed on the surface of F-MoS2-1 would take up some of the NO2 adsorption site. Additionally, the sample F-MoS2-2 with a higher F doping level demonstrated increased sensitivity. The F-MoS2-2 sensor’s high sensitivity was mostly due to the lattice fluorine filled to the sulfur vacancy, which generated impurity levels and reduced the energy required for its electronic transition. This study might contribute to the development of new molybdenum sulfide based gas sensor.