Detection of mercaptopurine drug by T4,4,4-graphyne and the effect of applied electric field: A densityfunctional theory study

In the present work, adsorption of mercaptopurine (MP) drug on T4,4,4-graphyne sheet is examined by usingdensity functional theory to explore the feasibility of T4,4,4-graphyne based sensor. The most stable configuration,charge transfer, adsorption energy, electronic band structures, and density of states are determined. It is foundthat weak physical adsorption with small charge transfer from T4,4,4-graphyne to MP drug took place. T4,4,4-graphyne sheet is an intrinsic semiconductor with a direct band gap. The energy band gap of T4,4,4-graphynesheet is sensitive to the MP adsorption and decreases with any decrease in the concentration of the MP drug.Hence, T4,4,4-graphyne is a good candidate to detect the MP drug and its concentration. The electronicproperties of T4,4,4-graphyne sheet with adsorbed MP are remarkably modulated by applying a perpendicularelectric field. The results reveal that applying the electric field is a helpful method to improve the sensingperformance of T4,4,4-graphyne sheet.