Potential application of C-MoS₂ monolayer for identifying lung cancer biomarkers in exhaled breath: a DFT study

This paper presents a computational study investigating the potential of MoS₂ and C-doped MoS₂ monolayers as breath sensors for detecting Volatile Organic Compounds (VOCs) associated with lung cancer (LC). The sensing characteristics of MoS₂ and C-MoS₂ towards LC-related VOCs were explored using Density Functional Theory (DFT) calculations. The exchange-correlation energy was calculated using the Generalized Gradient Approximation (GGA) with the Perdew-Burke-Ernzerhof (PBE) functional. Our finding showed VOCs associated with LC such as C₃H₄O, C₄H₈O, C₅H_8, and C₆H₁₂ interacted with the MoS₂ monolayer, with adsorption energies − 0.80 eV, -0.82 eV, -1.01 eV, and − 0.99 eV, respectively. However, the interaction is greatly enhanced by C-doped MoS₂ with adsorption energies − 2.04 eV, -2.12 eV, -1.85 eV, and − 2.25 eV, respectively for C₃H₄O, C₄H₈O, C₅H₈ and C₆H₁₂. Additionally, we investigated the impact of gas adsorption on the bandgap of the materials to assess their electrical variations. Pristine MoS₂ exhibited minimal changes in bandgap upon VOC adsorption. In contrast, C-MoS₂ displayed a remarkable increase in bandgap, ranging from 0.71 eV to 1.56 eV, compared to its initial value of 0.69 eV. This significant increase indicates an improved sensitivity of C-MoS₂ as a breath sensor for LC-related VOCs. Furthermore, we reported structural variations, density of states (DOS), charge transfer, work function, and recovery time analysis. Our results demonstrate that C-MoS₂ exhibits promising characteristics for detecting VOCs associated with LC.