Synthesis of low-cost 3D-porous ZnO/Ag SERS-active substrate with ultrasensitive and repeatable detectability

A novel 3D-porous ZnO/Ag SERS-active substrate with ultrasensitive and repeatable detectability is designed and prepared in this paper. Without using any expensive materials and complicated methods, this substrate obtains a lowest detectable concentration of 10−11 M for rhodamine and shows outstanding sensitivity for many other probe molecule as well, e.g., crystal violet, malachite green and Sudan I, etc. Benefitting from the improved photocatalytic activity of ZnO/Ag heterostructure, the substrate can entirely degrade the target molecules in situ under ultraviolet radiation for 30 min, and then 100 percent recover the detectability, which endows this base excellent repeatability. The enhancement mechanisms of this base are meticulously analyzed, and the finite-different time-domain simulations are introduced as well for further exhibiting the 'hot spots' distributions. The simple method and prominent Raman enhancement property make this base a quasi-commercial SERS-active substrate, which will certainly show promising applications in chemical and biological detection.