DFT Study on Adsorption of Volatile Organic Compounds on Silicene

Cancer can be regarded as a rising threat to modern societies. Detecting cancer at an early stage significantly improves the durability of the disease; unfortunately, currently available methods for early diagnosis of cancer are scarce and inefficient. In fact, the concentration of Volatile Organic Compounds (VOCs) in cancer patients in the breath is different from that in normal people. Therefore, the development of new sensors that can detect VOCs with low concentrations at the early stage of cancer, is desirable. 2D materials are expected as attractive materials for these sensors due to their large surface area to volume ratio. In this work, we investigated the adsorption mechanism of some small-to-medium VOCs on the surface of silicene by the quantum simulation method. The images of the potential energy surfaces for different positions of the adsorbate on the silicene surface were explored by Computational DFT-based Nanoscope for the determination of the most stable configurations and diffusion possibilities. The adsorption energy profiles were calculated by three approximations of van der Waals interaction: revPBE-vdW, optPBE-vdW, and vdW-DF2. It is found that the adsorption energies of the VOCs in question vary in the range of 0.6-1.0 eV, which indicates that silicene is considerably sensitive with these VOCs. The charge transfer between the substrate and VOCs was also addressed.