Controllable preparation of the Au–MoS2 nano-array composite: optical properties study and SERS application

Abstract

The controllability of materials that has attracted widespread attention is a key factor for improving the performance of SERS substrates. Hence, in this study, a kind of controllable materials constructed with Au nano-disk array and monolayer MoS₂ had been developed. The optical properties of the composite were studied and the Raman enhancement was obtained. Compared with the monolayer MoS₂, the peak of the above composite was slightly red-shifted, and the intensity was increased by about 2.5 times. This was due to the thermal effect and the internal quantum efficiency improvement of MoS₂ caused by the local surface plasmon resonance of Au. The simulation results of the finite-difference time-domain and the experimental results all showed an enhanced photoluminescence of the composite, which was attributed to the resonance wavelength of the Au nano-disk being adjusted to be consistent with the photoluminescence peak of the monolayer MoS₂. Through the synergistic action of the electromagnetic enhancement and chemical enhancement, the highly sensitive and stable surface-enhanced Raman scattering (SERS) active substrate constructed with Au-MoS₂ composite was sequentially utilized in the detection of antibacterial agent residues on the aquatic products. Thereafter, a calibration curve with ultralow limits of detection (LOD) at 10⁻¹⁵ M was established for the standard solutions of crystal violet (CV), and then the assay on shrimps was successfully realized. Therefore, this research provides an effective way for attractive SERS performance of MoS₂, and confirms the potential possibility for application on food safety and other trace detection.