Plasmonically Active Atomically Thin Titanium-Based Quasicrystals for Dopamine Sensing

Non-noble nanomaterial-based quasicrystals (QC) are attractive structures due to their potential surface plasmon resonance (SPR) properties and ability to be easily exfoliated into two-dimensional (2D) sheets. Interaction with and sensing of organic molecules are applications where such 2D materials are a viable option due to their large surface area to volume ratio, providing abundant active sites for molecular interactions. In this work, a titanium-based multicomponent alloy (Ti₄₅Zr₃₈Ni₁₇) was exfoliated into a 2D quasicrystal (2D-Ti QC) from its bulk form via liquid-phase exfoliation. Structural and optical experimental techniques were used to characterize the 2D-Ti QC. Its plasmonic nature was verified and demonstrated via the absorbance spectrum, light localization images, and far-field diffraction patterns. Dopamine sensing was demonstrated using the absorbance spectra of optically active 2D-Ti QC. The linear range of detection was obtained as ∼13–91 nM (200–1400 ppb). Molecular dynamics (MD) simulations of Ti QC were conducted to investigate its structural stability. The interaction between 2D-Ti QC and dopamine was investigated by using DFT simulations. In this way, the potential of 2D-Ti QC to be used as an organic molecule sensor has been experimentally and theoretically demonstrated.