Niobium disulfide nanosheets modified surface plasmon resonance sensors for ultrasensitive detection of mercury ion

Highlights: • We have developed a novel sensor based on niobium disulfide high perfect performance. • The maximum value of SPR sensitivities approached to 193°∕RIU achieved by coating the NbS₂ nanosheets in simulation calculation. • These sensors were used to detect mercy and the value of sensitivity is 13.55°∕μM, and detection limit approach 1 pM. -- Abstract: Mercury ion (Hg²⁺) can affect the quality of water and cause damage to human health. Therefore, the detection of Hg²⁺ in water, especially trace Hg²⁺, is very important. However, the detection limit (approximately 200 pM) of conventional Hg²⁺ sensors is far lower than the detection limit (7.5 pM) proposed by the US Environmental Protection Agency for measuring Hg²⁺. Here, we have developed a novel sensor based on niobium disulfide (NbS₂)'s high perfect performance. The maximum value of SPR sensitivities approached to 193°∕RIU achieved by coating the NbS₂ nanosheets in simulation calculation, which had increased by 38.1% compared with the case without NbS₂ overlayer. More importantly, this work also detected the ultra-low concentration of Hg²⁺ and describes the sensing mechanism of NbS₂ based SPR sensors. Surprisingly, these sensors were used to detect mercury and the value of sensitivity is 13.55°∕μM, and detection limit approach 1 pM. NbS₂ nanosheets based SPR sensors provided innovative design ideas for the development of ultra-sensitive detection technology.