Development of Transition Metal Dichalcogenides-based Sensors for the Selective Detection of Biomolecules

Abstract

The 2H-WS2 quantum dots (QDs) were effectively prepared through the simple solvothermal reaction of 1T-WS2 nanosheets via the dimension and phase engineering. The chemical exfoliated 1T-WS2 nanosheets in N-methyl-2-pyrrolidone (NMP) derived their phase transition and chopping at mild conditions (100oC, 90 min) to produce 2H-WS2 QDs. The phase transition and chopping process shows dependent solvent. WS2 QDs were not synthesized in 1,4-dioxane and dimethyl sulfoxide. As-prepared 2H-WS2 QDs had 2.8 nm in average size with a lateral spacing of 0.27 nm. The strong absorption in visible range and a highly increased quantum yield (5.7%) for fluorescence emission with excitation wavelength dependency. The WS2 QDs were successfully applied for the selective, sensitive and rapid detection of dopamine in human serum. The WS2 QDs strong fluorescence of was selectively quenched by dopamine while other neurotransmitters and interferences such as norepinephrine, epinephrine, ATP, ascorbic acid, and uric acid did not influence their fluorescence. The fluorescence of WS2 QDs was quenched the addition of dopamine and Au3+ ions owing to fluorescence resonance energy transfer between WS2 QDs and the formed Au nanoparticles. This sensing mechanism responsible for the selective detection of dopamine was demonstrated in this work.