Liquid-Gated Graphene Field Effect Transistor for High-Performance Label-Free Sensing of Polycyclic Aromatic Hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) are one of the most toxic environmental pollutants, which are very harmful to the human body. It is crucial to find convenient and effective detection methods of PAHs for preventing and controlling environmental pollution. Low-dimensional material-based field effect transistor (FET) sensors exhibit the advantages of a small size, simple structure, fast response, and high sensitivity. In this work, graphene (Gr) has been selected as the channel material for FET sensors for PAH detections. Through π-π electron stacking interactions, PAHs could be spontaneously adsorbed on the surface of the Gr and affect its electronic carrier transport behavior. Based on the relationship between the concentrations and the changes in the Dirac point of the Gr, the sensor achieved an effective response to PAHs in a broad range from 10−10 to 10−6 mol/L and a limit of detection of 10−10 mol/L was obtained, which was lower than that provided by the World Health Organization (3.46 × 10−9 mol/L), in drinking water. The results demonstrate a great application of the FET sensors in environmental analysis, and provide an important way for rapid and in situ monitoring of PAHs.