Electrochemical Sensor Based on Black Phosphorus for Antimony Detection Using Dip-Pen Nanolithography: The Role of Dwell Time.

Heavy metals, including Sb, are major pollutants with limits on their allowed concentration in drinking water. Therefore, there is a need for sensitive, simple, and portable detection methods for which electrochemical sensors are ideally suited. In this current study, Meta-chemical surfaces are developed for electrochemical sensing by patterning gold electrode surfaces with a mixture of black phosphorus (BP) and polymethyl methacrylate (PMMA) as nanoclusters using dip-pen nanolithography. It is found that the surface-to-volume ratio (S/V), fill factor, and ink composition affect the sensitivity of the sensor for Sb detection. The S/V ratio and fill factor can be altered by the dwell time, which has a complex effect on the limit of detection (varying from 14 to 24 ppb with the changes in the dwell time). Density functional theory calculations show that the binding between Sb(III) and BP is more exergonic in the presence of PMMA. These results are significant because they allow for the development of more sensitive Sb sensors, which can affect the wider field of the detection of heavy metals in drinking water sources and achieve higher efficiency than the commonly used instruments.