Flexible Ag SERS substrate for non-destructive and rapid detection of toxic materials on irregular surface

In this study, silver (Ag) is deposited onto polyester fabric through a magnetron sputtering system. The argon flow rate and sputtering time are both controlled to produce Ag nanoparticles of different sizes on the polyester substrate with different gap distances. The scanning electron microscope images, X-ray diffraction spectra, and Raman intensity are used to evaluate the produced substrates. With an average grain size of similar to 46 nm, Ag particles deposited at an argon flow rate of 200 sccm on polyester fabric (AP-200) provides the best SERS performance of 33,625.34 counts towards a 10(-3) M MB solution. The results show that the AP-200 SERS substrate is highly sensitive, reproducible and stable, and it also demonstrates good reusability. Image of "hotspots" that forms between two Ag nanoparticles based on electric field distribution is simulated by the finite-difference time-domain (FDTD) method which is used to explain the phenomenon of signal enhancement. In addition, AP200 is used to directly collect R6G from an irregular surface, and shows high sensitivity with a limit of detection of 1 ppm.