Real-time electronic sensor based on black phosphorus/Au NPs/DTT hybrid structure: Application in arsenic detection

Field-effect transistor (FET)-based sensors are now attracting increasing attention due to their high sensitivity, low-cost, convenient fabrication, and portability. Black phosphorus (BP) nanosheet, due to its unique structure and excellent electronic properties, becomes a promising candidate for high-performance sensing material in an FET sensor. Here, we report an FET sensor using hybrid structure of BP and dithiothreitol (DTT)-functionalized gold (Au) nanoparticles (NPs) for the detection of Arsenic (As) in water. The performance of the as-fabricated sensor is outstanding with a lower limit of detection (LOD) of 1 nM, which is much lower than the maximum contaminant level (MCL) for As ions in drinking water (130 nM) advised by the U.S. Environmental Protection Agency (EPA). The sensor also shows a rapid response (within 1-2 s) and good selectivity against other metal ions (e.g., Hg2+, Ca2+, Cd2+, etc.). The rapid, selective, sensitive and stable sensing performance suggests a strong potential of this sensor platform for in-situ detection of As in water, either as a standalone device or being assembled into existing water equipment to continuously monitor water pollutants.