Surface-enhanced Raman scattering from amorphous nanoflower-structural Nb2O5 fabricated by two-step hydrothermal technology

Semiconductor surface-enhanced Raman scattering (SERS) substrates are showing increasing potential due to their high chemical stability and selective enhancement to probe molecules. Simultaneously, semiconductors have a greater controllability and more flexible SERS regulation strategy relative to precious metals. The tailored shape design not only can affect the SERS performance of noble metal but also can work on semiconductor SERS-active substrates. Here, for the first time, a special nanoflower structure composed of wrinkled amorphous nanosheets is introduced into the promising semiconductor SERS-active substrate Nb2O5 to improve its SERS performance. The Nb2O5 nanoflower clusters with a mean diameter of 262 nm were prepared by a simple and original two-step hydrothermal method, and exhibited a detection limit of 10−7 M when detecting crystal violet molecules. Owning to the special nanoflower structure assembled by nanosheets, the substrate possesses a large specific surface area, which is conducive to the adsorption of more probe molecules. In addition, the good SERS performance should also be attributed to the synergistic effect of ~102 electromagnetic field enhancement of Nb2O5 nanoflower, as well as the strong charge transfer resonance in this substrate-molecule system under the 532 nm incident laser.