Analysis of 2D nanomaterial BC₃ for COVID-19 biomarker ethyl butyrate sensor

Ethyl butyrate (EB) was identified in recent research as a prominent biomarker of COVID-19, as concentrations of EB were higher in exhaled breath of COVID-19 patients. Electronic sensitivities of pristine, Al- and Si-doped BC₃ nanosheets to the EB molecule were investigated in this study using density functional theory. It is found that the pure BC₃ was ineffective in sensing EB due to low adsorption energy and sensitivity. Aluminum- and silicon-doped BC₃ nanosheets were effective in forming a strong interaction with EB and were also sensitive. Our calculations show that the band gaps of the Al-doped and Si-doped BC₃ sheets were significantly decreased upon EB adsorption, which increased the electrical conductance of the sheets and the sensitivity. However, Si-doped BC₃ had a recovery time of almost 22 hours, making it less potent than Al-doped BC₃, which had a recovery time of just 7.7 minutes. The shorter recovery time of the Al-doped BC₃ sheet is due to its moderate adsorption energy of 25.8 kcal mol^-1. These results can help facilitate the development of an EB biosensor for COVID-19 testing and other similar applications.