CVD-Grown MoS₂ Monolayer-Based Ultrasensitive Hg²+ Ion Sensing in Water

Mercury (Hg) is widely acknowledged as one of the most hazardous heavy metals, even in trace amounts. Its presence poses the risks of both chronic and acute poisoning, leading to serious health issues, including cancer, nerve damage, acrodynia, and movement disorders, which can ultimately result in fatalities. Current mercury sensing devices have several disadvantages, including sluggish response times, high cost, and limited portability. In this study, we present an interdigitated electrode-based sensor with molybdenum disulfide (MoS2) as the sensing layer to detect trace amounts of toxic Hg $^{{2}+}$ ions. The MoS2 layer has been synthesized using a chemical vapor deposition (CVD) system and transferred to the interdigitated device through an energy-assisted wet transfer method. Comprehensive characterizations have confirmed the successful synthesis and transfer onto the IDE device. The fabricated sensor exhibits remarkable performance with excellent selectivity toward Hg $^{{2}+}$ ions, an impressive limit of detection of 27.9 part per trillion (ppt), a remarkable sensitivity of $957~\mu $ A/ppb, and a quick response time of less than 4 s.