Selective room-temperature dimethylformamide vapor sensing using MoSe2-rGO composite synthesized via facile hydrothermal method

Two dimensional semiconductors such as MoSe2 with large specific surface area, bandgap in visible region and high carrier mobilities have attracted a greater attention as a sensing platform. A composite of MoSe2 and reduced graphene oxide (rGO) has been successfully synthesized using a facile hydrothermal method and used as a gas sensing platform for the room-temperature detection of dimethylformamide (DMF). Structural analysis has revealed the formation of MoSe2/rGO composite along with the presence of MoO3 due to partial oxidation of MoSe2 into MoO3. In addition, the presence of J2 mode (150.6 cm−1) in Raman spectra and 3d doublet with lower spin-orbit splitting in XPS spectra indicated the presence of 1T-MoSe2 in addition to main 2H-MoSe2. Sensor displayed a sensitive and selective detection of DMF down to 2 ppm with response (recovery) time of 130 s (50 s) and a relative response of 3.6 %. Present work highlights the role of optimum weight ratio in determining the overall sensing performance of the sensing devices. The advantages of repeatability, selectivity and excellent stability, provide a great possibility for the use of MoSe2/rGO-based composites in sensing.