Agent-free, highly sensitive, and simply operated Ag⁺ sensor with molybdenum disulfide-based field effect transistor

Ag⁺, as a good bactericidal reagent, has been extensively used to prevent the growth and spread of bacteria and viruses. However, overcommit of Ag⁺ would leave residues in environments, which is toxic to the human body even under minimal exposure. In this case, a fast and high selective sensing method based on field effect transistors (FET) has been proposed for monitoring Ag⁺ in aqueous solutions. Through coordination interaction, Ag ⁺ could be spontaneously adsorbed on the surface of the sensing material MoS₂ and affect its electronic carrier transport behavior. The MoS₂-based FET sensor show outstanding sensing performance to Ag⁺ including short response time (60 s), good linear relationship (R² = 0.97), low detection limit (10^-10 mol/L) and high selectivity, which could meet the permissible criterion of Ag⁺ in drinking water by the World Health Organization (0.93 × 10^-6 mol/L). This study will promote the application of FET sensors in environmental analysis, and provide important guidance to realize rapid, on-site or in-situ monitoring of heavy metals in aqueous solutions.