Single sea urchin–MoO3 as a SERS substrate

R. Prabhu B, K. Bramhaiah, K. K. Singh and N. S. John, Nanoscale Adv., 2019, 1, 2426-2434

Sea-urchin shaped hydrated MoO3 nanostructures have been synthesized employing a simple chemical bath deposition technique. The sea-urchin MoO3 has a core region covered by multitude of long spikes of 10 µm average length. The spikes have tapered tips of average diameter 10 nm. Sea-urchin MoO3 is tested for SERS activity of rhodamine 6G (R6G). It showed a detectionlimit as low as 100 nM. The enhancement factor is found to be as high as 1× 105 and 7× 104 for 612 cm-1 and 1358 cm-1 signal of R6G molecule. Moreover, the substrate can be reused for many cycles exploiting the photocatalytic activity of MoO3. The enhancement in the Raman signal arises due to the charge transfer mechanism of analyte molecule to the substrate. The availability of oxygen vacancies, surface hydroxyl groups as well as defects in the nanostructures provides active sites for adsorption of analyte molecules. The developed single nanostructure based SERS substrate has a great potential towards efficient detection of industrial dye pollutants.