Rapid‐Response and Portable Lead Ion Sensor Using Co/Pt/Si Schottky Heterojunction Without Reference Electrode

Abstract Lead ions (Pb 2+ ) are classified as highly toxic heavy metals that pose substantial threats to both human health and environmental integrity. Consequently, the sensitive detection of Pb 2+ , particularly at low concentrations, is imperative for the purposes of environmental surveillance and safeguarding public health. Here, we introduce a Co/Pt/Si Schottky heterostructure for a rapid, portable Pb 2+ detection sensor. One electrode of the heterojunction serves as a Pb 2+ probe, and sensor processing circuits are integrated. The Co/Pt thin films were deposited via magnetron sputtering on a Si(100) substrate, followed by heterojunction fabrication using semiconductor process technology. The sensor is functionalized with a glutathione‐modified gold electrode, leveraging the sulfur‐donor properties of cysteine in glutathione and the electron‐acceptor behavior of Pb 2+ . This interaction modulates the surface potential of the gold electrode, altering the current‐voltage rectification of the Co/Pt/Si heterojunction. A two‐terminal configuration enables current signal readout without reference electrodes. The sensor demonstrates a linear response to Pb 2+ concentrations ranging from 1×10 −8 to 1×10 −3 mol/L, with high selectivity attributed to the affinity of glutathione for Pb 2+ . The key benefits are the simplicity of its fabrication process and its portability, which are enhanced by the integration of measurement circuitry. This makes the sensor a promising candidate for rapid, on‐site detection of heavy metal ions in applications related to health and environmental monitoring.