Highly selective and sensitive lung cancer molecule detection by two-dimensional C2N monolayer

Rapid and reliable detection of hazardous chemicals is critical for environmental monitoring, industrial safety, and human health. Two-dimensional (2D) porous materials have emerged as promising platforms for chemical sensing due to their high surface activity, tunable electronic structure, and excellent environmental stability. In the present study, we systematically investigate the adsorption mechanism of several volatile organic compounds (VOCs), including C4H8Cl2S, C2H4Cl2O, C2H6O, C6H7N, and C7H9N, on a C2N monolayer using first-principles calculations. Adsorption energies, charge transfer (ranging from ∼0.16 |e| to 0.19 |e|), and work function variations (0.20–0.65 eV) were evaluated to quantify molecule-dependent interactions and electronic perturbations. The results show pronounced charge redistribution along with slight bandgap modifications caused by molecular states near the Fermi level, indicating that the adsorption process is physisorptive in nature. The sensitivity response values are found to be 11.57, 8.71, 7.70, 5.39, and 3.44 for C4H8Cl2S, C2H4Cl2O, C2H6O, C6H7N, and C7H9N VOCs on C2N surface, respectively. Transport analysis using the non-equilibrium Green function formalism shows distinct suppression or enhancement of zero-bias transmission channels and characteristic I–V responses for each VOC, effectively creating ON and OFF current signatures for molecular recognition. Estimated recovery times from sub-microseconds to a few microseconds suggest rapid desorption and sensor reusability at room temperature. Overall, these results demonstrate that the C2N monolayer is a promising candidate for highly sensitive and selective VOC detection. Its performance suggests broad applicability in environmental and industrial safety monitoring and in early warning systems for exposure to cancer-related chemicals, as many VOCs are known to be associated with cancer and other severe health risks.