Dopamine Detection Based on Low-Voltage Oxide Homojunction Electric-Double-Layer Thin-Film Transistors

Quick and accurate detection of dopamine (DA) is of great significance for routine analysis and biomedical diagnosis. Here, low-voltage indium-zinc-oxide (IZO) homojunction electric-double-layer (EDL) transistors using nanogranular SiO2 electrolytes as the gate dielectrics are proposed for DA detection. A DA detection limit of 0.1 nM with good selectivity is obtained at a low voltage of 0.8 V. The DA sensing mechanism can be attributed to the modulation of surface potential of the indium-tin-oxide (ITO) gate electrode by preferential binding of DA molecule to phenylboronic acid. Such low-voltage oxide-based EDL transistors have potential application in biochemical sensors.