Pulsed-Electrodeposited 3D Silver Dendrites on Bamboo-like TiO2 Nanotubes for Ultrasensitive SERS Detection

A surface-enhanced Raman scattering (SERS) substrate based on three-dimensional silver dendrites (AgDs) was developed on bamboo-like TiO2 nanotubes (BTNTs) fabricated through alternating voltage anodization. The AgDs were grown by short-pulse current electrodeposition, which promoted hierarchical and vertical formation, a process favored by self-formed oxide cracks and axial segmentation in the BTNTs. This fractal 3D architecture results in a high density of hot spots, intensifying the local electric field. Methylene blue was used as the probe molecule, yielding clear Raman signals at concentrations as low as 1×10-10 M. The limit of detection was calculated to be 1.6 × 10-11 M, with an analytical enhancement factor of 3.0 × 10⁷. This work provides a reproducible, scalable, and cost-effective route to fabricate high-performance SERS substrates in various real applications.