DFT study of MoSe2 monolayers for cohesive adsorption of harmful gases CO, CO2, SO2, and NF3

Abstract

According to the World Health Organization, contact with atmospheric airborne pollutants (CO, CO₂, SO₂, and NF₃) causes 4.2 million deaths annually. Globally, there is a well-established demand for highly sensitive, inexpensive, tiny, and energy-efficient gas sensors that are able to recognize and steer clear of high pollution hotspots. Density functional theory (DFT) is utilized to analyze the electronic properties of CO, CO₂, SO₂, and NF₃ gases in the MoSe₂ monolayer for gas sensing mechanism. On MoSe₂, calculations and discussions are made on the adsorption energies and configurations that are most stable. A detailed analysis is conducted on the adsorption distance (d (Å)), charge transfer (Q_T), adsorption energy (E_ads), band gap (E_g), density of states (DOS), electron difference density (EDD), and Recovery time \(\left( \tau \right)\). The outcomes attained demonstrate that the adsorption of CO, CO₂, SO₂, and NF₃ gases significantly alters the electrical characteristics as well as the adsorption of MoSe₂ monolayer. However, in comparison to CO, CO₂, and SO₂, the MoSe₂ monolayer system shows larger adsorption energy towards NF₃ and a higher sensitivity. The transport characteristics employing the non-equilibrium Green's function (NEGF) method validate the efficiency of the MoSe₂ monolayer in terms of considerable current–voltage (I–V) response for enhanced CO, CO₂, SO_2, and NF₃ gas sensing. Compared to CO, CO₂, and SO₂, MoSe₂ has a much higher sensitivity to NF₃.