Electro-optical sensors based on two-dimensional c3n2 structures for non-invasive gastric cancer detection: A first-principles study

Abstract

In this study, we examined the potential of two newly predicted two-dimensional carbon nitride structures, namely P-C₃N₂ and I-C₃N₂, for use as sensors using density functional theory. The electronic and optical properties of monolayer and bilayer C₃N₂ sheets are studied, with a focus on their sensing capabilities for acetone, a volatile organic compound commonly found in the breath of individuals diagnosed with gastric cancer. Our findings indicate that the interaction between acetone and C₃N₂ sheets primarily involves physisorption, characterized by low adsorption energies. This weak binding enables easy desorption, enhancing the reusability of the C₃N₂ sheets as sensors. The semiconducting properties of the I-C₃N₂ sheet are not sensitive to acetone adsorption, whereas the P-C₃N₂ sheet exhibits a significant change in its band gap upon acetone adsorption. As the concentration of adsorbed acetone molecules increases, the band gap of monolayer and bilayer P-C₃N₂ sheets decreases, resulting in improved electrical conductivity. Moreover, it is demonstrated that the optical properties of monolayer and bilayer P-C₃N₂ are responsive to the presence and concentration of the acetone molecules. Our findings suggest that the P-C₃N₂ sheets have great potential as sensing materials for diagnosing gastric cancer through the detection of exhaled gases, even in the presence of interfering molecules.