MoSe₂ nanosheets for detection of methanol and ethanol vapors: A DFT study

We report the adsorption properties of methanol (ML) and ethanol (EL) vapor molecules on to the monolayer MoSe₂ surface. Before, studying the adsorption behavior, the structural stability of MoSe₂ monolayer is ensured with formation energy. The stable monolayer MoSe₂ nanosheet is used as a base material for the adsorption of ML and EL vapor molecules. The interaction of ML and EL vapors on MoSe₂ surface layer is explored using the adsorption energy, energy gap variation and Bader charge analysis. We noticed the band gap variation between 1.43 and 1.88 eV upon adsorption of methanol and ethanol vapors on to MoSe₂ nanosheets. Also the adsorption energy is found in the range of -0.375 to -0.732 eV upon the interaction of alcohol molecules on MoSe₂ flakes. Besides, the density of states (DOS) spectrum and electron density clearly envisions the adsorption properties of ML and EL vapors on to the MoSe₂ monolayers. Furthermore, a short recovery time is noticed for MoSe₂ nanosheet material upon desorption of methanol and ethanol molecules. Moreover, the variation in the resistance of MoSe₂ base material is noticed upon adsorption of ML and EL molecules. The findings show that monolayer MoSe₂ nanosheets can be used as a chemi-resistance to detect the presence of ML and EL vapors in the environment.