Ag loaded TiO2 nanotube photonic crystals self-doped Ti3+ periodically by anodization process and their performance of surface enhanced Raman scattering

Here, the preparation of TiO2 nanotube photonic crystals (PCs) and their periodical Ti3+ self-doping were synchronously accomplished for forming Ti3+-TiO2 PCs by introducing an appropriate reduction pulse voltage (-4 V) into the periodical anodic oxidation voltage waveform. Subsequently, some Ag nanoparticles were deposited on the surface of the Ti3+-TiO2 PCs by vacuum evaporation for getting Ag/Ti3+-TiO2 PCs nanostructures, which were ideally suited for the surface-enhanced Raman scatting (SERS) substrates. Compared to the Ag loaded TiO2 nanotubes, the SERS signal of the Ag/Ti3+-TiO2 PCs for RhB can be improved 8.4 times. The desirable SERS property would be attributed to the synergistic effects of the localized electromagnetic (EM) field enhancement and charge-transfer (CT) chemical enhancement mechanisms, which was also discussed in detail.