Detection of mercaptopurine drug by T۴,۴,۴-graphyne and the effect of applied electric field: A density functional theory study

In the present work, adsorption of mercaptopurine (MP) drug on T۴,۴,۴-graphyne sheet is examined by using density functional theory to explore the feasibility of T۴,۴,۴-graphyne based sensor. The most stable configuration, charge transfer, adsorption energy, electronic band structures, and density of states are determined. It is found that weak physical adsorption with small charge transfer from T۴,۴,۴-graphyne to MP drug took place. T۴,۴,۴-graphyne sheet is an intrinsic semiconductor with a direct band gap. The energy band gap of T۴,۴,۴-graphyne sheet is sensitive to the MP adsorption and decreases with any decrease in the concentration of the MP drug. Hence, T۴,۴,۴-graphyne is a good candidate to detect the MP drug and its concentration. The electronic properties of T۴,۴,۴-graphyne sheet with adsorbed MP are remarkably modulated by applying a perpendicular electric field. The results reveal that applying the electric field is a helpful method to improve the sensing performance of T۴,۴,۴-graphyne sheet.