Effect of fluorine doping on the NO₂-sensing properties of MoS₂nanoflowers

The somewhat slow recovery kinetics of NO₂sensing at low temperatures are still challenging to overcome. To enhance the gas sensing property, fluorine is doped to MoS₂nanoflowers by facile hydrothermal method. Extensive characterization data demonstrate that F was effectively incorporated into the MoS₂nanoflowers, and that the microstructure of the MoS₂nanoflowers did not change upon F doping. The two MoS₂doped with varying concentrations of fluorine were tested for their sensing property to NO₂gas. 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 NO₂adsorption 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.