Capillarity‐Assistant Assembly: A Fast Preparation of 3D Pomegranate‐Like Ag Nanoparticle Clusters on CuO Nanowires and Its Applications in SERS

A 3D pomegranate‐like “Ag nanoparticle clusters/CuO nanowires” heterostructure is designed and prepared by a fast two‐step method with assistance of capillarity in this paper. Owing to the abundant “hot spots” generated in the gaps of Ag nanoparticle clusters and the improved electromagnetic mechanism caused by the charge transfer effect between Ag/CuO interface, this heterostructure shows outstanding Raman performance with the enhancement factor as high as 3.30 × 109. Both the formation process and the Raman enhancement mechanism of this heterostructure are meticulously analyzed, and the finite‐different time‐domain and first‐principles simulations are also introduced here to further verify some conjectures. Moreover, this heterostructure shows a certain level of crock resistance, which endows the base a well durability. This paper provides a fast and dexterous way in preparing low‐cost and high‐sensitivity surface enhanced Raman scattering (SERS)‐active substrate, which will show promising applications in chemical or biological detection.