Aromatic Volatile Organic Compounds Adsorption on Tungsten Diselenide Monolayer

Abstract

In this work, we performed a density functional theory calculation to systematically investigate the adsorption and evaluate the adsorption performance of aromatic volatile organic compounds, benzene and toluene, on WSe2 monolayer. The most favourable adsorption configurations of gas molecules with the parallel orientation of the benzene ring to the substrate surface are explored by computing the binding energies as a function of spatial coordinates and carefully optimizing geometrical structures. The calculations pointed out that gas molecules could diffuse across the substrate along the diffusion paths with quite low diffusion potential barriers, about 180 meV for benzene and 130 meV for toluene molecules. We found that both gases are physisorbed on WSe2 monolayer with moderate adsorption energies, short recovery times, and large response lengths. The gas adsorption causes the bandgap reduction of 26 meV and a slight work function increase of the substrate. There is a charge transfer from the substrate onto the gas molecules, this may cause a resistance decrease of the p-type semiconductor substrate. WSe2 monolayer is quite sensitive to benzene and toluene, and could be suggested as an aromatic gas sensing material.

First-principles study of highly sensitive graphene/hexagonal boron nitride heterostructures for application in toxic gas-sensing devices

“…This tool uses the adsorbate as a scanning tip, moves the gas molecule across the graphene or graphene/h-BN heterostructures, and rotates around its center of mass 34 to obtain the high-resolution energy landscape. The potential energy landscape or the adsorption energy of the system can be determined as follows: 31,32 E ads = E complex − E saturation , where E complex and E saturation are the total energy of the gas + graphene or gas + graphene/h-BN heterostructures, and the total energy of the system in which the gas molecule and the graphene (graphene/h-BN) are isolated, respectively.…”

“…Upon adsorption, the precise molecule positions and orientations are crucial for evaluating the optimal geometrical congurations. Thus, we employed the high-resolution computational DFT-based Nanoscope tool [31][32][33] to scan through all possible congurations to obtain the potential energy surface (PES) and the binding energy prole. This tool uses the adsorbate as a scanning tip, moves the gas molecule across the graphene or graphene/h-BN heterostructures, and rotates around its center of mass 34 to obtain the high-resolution energy landscape.…”

“…This tool uses the adsorbate as a scanning tip, moves the gas molecule across the graphene or graphene/h-BN heterostructures, and rotates around its center of mass 34 to obtain the high-resolution energy landscape. The potential energy landscape or the adsorption energy of the system can be determined as follows: 31,32…”