Uncovering efficient sensing properties of vanadium disulfide (VS₂) nanosheets towards specific neurotransmitters: A DFT prospective

Designing efficient nanosensors based on ultrathin materials for the detection of neurotransmitters is crucial for biosensing applications. In this work, using spin-polarized density functional theory (DFT) calculations, structural, electronic, magnetic, and adsorption of the selected neurotransmitters, such as dopamine (DA) and histamine (HA), were investigated using light transition metals dichalcogenides, vanadium disulfide (VS₂) nanosheets. It was revealed that DA and HA adsorbed relatively weakly on pristine (p-VS₂) as well as single sulfur (S) Vacancy-induced (SV-VS₂). However, the introduction of selected transition metals (TMs) dopants, such as cobalt (Co), iron (Fe), and nickel (Ni), significantly improved the adsorption of DA and HA. Among the studied systems, Ni-doped VS₂ (Fe-doped VS₂) exhibited the strongest adsorption toward DA (HA) with an adsorption energy of −2.00 (−1.28) eV, which is promising for practical sensing applications. Charge analysis revealed that both DA and HA acted as charge donors to the TMs-doped VS₂. Upon DA/HA adsorptions, quantifiable variations were observed in the electronic structures and magnetic properties of TMs-doped VS₂, which were studied through band structures, spin-polarized density of states, and work function calculations. Lastly, for the practical detection capabilities at diverse pressure and temperature settings, we employed the Langmuir adsorption model. It was found that TMs-doped VS₂ detected DA and HA at concentrations ranging from tens of ppt to ppm levels, respectively. We strongly believe that our findings will contribute towards the development of highly effective nanosensors based on TMs-doped VS₂ nanosheets for the detection of DA, and HA.