3D hybrid MoS2/AgNPs/inverted pyramid PMMA resonant cavity system for the excellent flexible surface enhanced Raman scattering sensor

It is widely accepted that resonant cavity system represents the effective laser utilization due to the back and forth reflection and the electric field energy storage. Here, a three-dimensional (3D) hybrid MoS2/AgNPs/inverted pyramid polymethyl methacrylate (iPPMMA) resonant cavity system as a flexible surface enhanced Raman scattering (SERS) sensor was investigated in experiment and theory. The obtained resonant cavity between MoS2, iPPMMA and the plasmonic silver nanoparticles offers the tremendous local near-field enhancements, which is manifested using the finite-difference time-domain (FDTD) theoretical simulation. Additionally, by virtue of the lower light absorption, the iPPMMA gains the advantage over pyramid Si (PSi) in term of enhancing local electric field. The synergistic effects of MoS2, iPPMMA and AgNPs can generate the 3D dense hot spots and extremely contribute to the excellent ultrasensitivity, stablity, reproducibility and recyclability of the proposed flexible SERS sensor. Moreover, the fabricated MoS2/AgNPs/iPPMMA hybrid structure was housed at the end of the optical fiber to remotely detect the toxic mixtures solution, which demonstrates our flexible SERS sensor has enormous potential to be applied in food safety field.