Adsorption of gas molecules on a C3N monolayer and the implications for NO2 sensors

Recent reports have raised exciting prospects for the use of C3N monolayers exhibiting excellent adsorptive properties in nanodevice applications. In this study, we carried out first-principle calculations to investigate the adsorption of NO2, NO, CO, HCN, NH3, CO2, H2, N2, CH4, H2O, O2, and N2O gas molecules on a C3N monolayer as well as its potential applications in gas sensor devices. Our results reveal that the chemisorption of NO2 can significantly influence the electronic properties of the C3N monolayer (e.g., changing semiconducting behavior to conducting behavior). In contrast, physisorption of the other gas molecules had little effect on the electronic properties of the C3N monolayer. These results suggest that the C3N monolayer is much more sensitive and selective to NO2 than to the other gases. The recovery time of NO2 at T = 300 K is only 0.62 s. Moreover, the optical properties of the C3N monolayer can be modified as a result of the adsorption of different molecules, especially the NO2 molecule. Thus, the C3N monolayer is a promising and desirable candidate for use as a suitable material in gas sensors for NO2 detection.