Self-assembled vertically aligned silver nanorod arrays prepared by evaporation-induced method as high-performance SERS substrates

The substrates formed by the self-assembly method of metal nanoparticles are widely used in the molecular detection due to their high uniformity and good SERS properties. In this paper, we used the sliver nanorods as the building block for the first time to produce close-packed vertical arrays via evaporation-induced method. The results showed that the optimized substrates have good performance with excellent enhancement factor (4.47 × 105) and high reproducibility. By the time, we explore the relationship between the length of silver nanorods and the intensity of 4-mercaptobenzoic acid (4-MBA). The optimal SERS performance depended on longest silver nanorod length. In addition, the optimized vertical silver nanorod substrates exhibit 3 times than the optimized six-layer three-dimensional horizontal ones. Furthermore, the optimized substrate was able to directly detect malachite green (MG) down to 10−9 M. At the same time, the on-site detection of the thiram in the peel of apple is as low as 0.1 ng cm−2. The experimental results clearly show that our substrates have great potential for environmental monitoring, food safety and security application.