Study on the superior gas sensing and adsorption performance of Al-doped, P-doped and AlP pair doped stanene monolayers in the detection of CO gas molecules

In the present paper, the electronic properties and adsorption effects of P, Al and pair Al P doping over the stanene substrates were investigated based on theoretical modeling using density functional theory outlook. Then, the gas adsorption capacity of the elemental doped systems was examined to exploit the superior gas sensing efficacy. Stanene monolayers modified by Al and P atoms exhibit strong tendency to adsorb gas molecules in the environment. Based on our findings, Al-doped and P-doped stanene systems can serve as an applicable candidate for trapping toxic CO gases with great sensitivity. For the C-end position, the desorption strength (energy) of CO gas is much greater than that in O-end position, validating the stronger chemisorption of carbon atom of CO on the modified stanene surface. Considering the charge density difference analysis, we found a main accumulation of charge density above the adsorbed CO molecule, demonstrating the chemical nature of reaction at the interface of CO gas and stanene substrate. Therefore, the Al and P doped stanene monolayers are expected to be more effective for trapping CO molecules than the intrinsic stanene.