Demonstration of a Sensitive and Stable Chemical Gas Sensor Based on Covalently Functionalized MoS₂

Chemically exfoliated MoS2 was covalently functionalized and characterized as a chemically sensitive vapor sensor using changes in dc electrical resistance to detect a variety of volatile organic compounds (VOCs). Regardless of the polarity of the functionality introduced to the surface, sensors derived from functionalized MoS2 showed high sensitivity for polar and nonpolar VOCs. Additionally, MoS2 functionalized with trifluoromethyl benzyl bromide exhibited a very high sensitivity to polar and nonpolar organic vapors relative to the electrical resistance response of 2H MoS2, 1T′ MoS2, or carbon black/polymer composite chemiresistive vapor sensors. Chemically functionalized MoS2 sensors retained >70% of their initial responsiveness to test analytes after at least 72 h in air.