Controllable synthesis of the homogeneous 3D Ag nanoflowers on FTO substrate for ultra-sensitive SERS detection

High-efficient SERS substrates containing dense hot spots were fabricated by assembling 3D Ag nanoflowers (AgNFs)@Au-FTO substrate by using citrate ions as the shape-guiding agent. The vertical growth of 3D AgNFs could be attributed to the synergistic effects of the concentration gradient layer of Ag+ and the density gradient of the charge carrier. Combined with the simulation result of FDTD method, the enhanced SERS sensitivity and repeatability of AgNFs@Au-FTO could be attributed to the enlarged specific surface area, and the improved density of hot spots contributed by the overlap between the vertically stacked AgNSs with a high population of sharp edges.

Automated summary

High-efficient SERS substrates containing dense hot spots were fabricated by assembling 3D Ag nanoflowers@Au-FTO substrate using citrate ions as the shape-guiding agent. The vertical growth of 3D AgNFs was attributed to the synergistic effects of the concentration gradient layer of Ag+ and the density gradient of the charge carrier, leading to enhanced SERS sensitivity and repeatability. The improved density of hot spots was contributed by the overlap between the vertically stacked AgNSs with a high population of sharp edges.