Selective Detection of Cu(2+) Ions by Immobilizing Thiacalix[4]arene on Graphene Field-Effect Transistors

[Image: see text] Highly accurate quantitative detection of heavy metals is essential for environmental pollution monitoring and health safety. Here, for selective detection of Cu(2+) ions with high sensitivity, thiacalix[4]arene (TCA) immobilized on graphene field-effect transistors (G-FETs) are developed. Our proposed TCA-immobilized G-FETs are successfully used to detect Cu(2+) ions at concentrations ranging from 1 μM to 1 mM via changes in their transfer characteristics. Moreover, the measured transfer characteristics clearly shift only when Cu(2+) ions are introduced in the buffer solution despite it containing other metal ions, including those of Na(+), Mg(2+), Ni(2+), and Cd(2+); this selective detection of Cu(2+) ions is attributed to the planar arrangement of TCA on graphene. Therefore, TCA-immobilized G-FETs selectively detect Cu(2+) with high sensitivity.