Applied Surface Science, Vol.478, 737-743, 2019
Hierarchical micro/nanostructured TiO2/Ag substrates based on femtosecond laser structuring: A facile route for enhanced SERS performance and location predictability
Hierarchical micro/nanostructured TiO2/Ag substrates for surface-enhanced Raman scattering (SERS) application are fabricated by depositing Ag nanoparticles on the surface of TiO2 hierarchical micro/nanostructures, which are formed by combining femtosecond laser structuring with scalable hydrothermal treatment. Our results show that the morphology of hierarchical micro/nano TiO2/Ag architectures can significantly influence SERS performance. Compare with one-dimensional TiO2/Ag nanostructures hydrothermally fabricated on laser untreated Ti surface, a four-fold enhancement is shown in the SERS signal with excellent reproducibility. Most importantly, enhancement is significantly stronger in the valleys of our microstructures than on the hills due to geometrical orientation of nanostructures on the surface of the microstructure. The site predictability for SERS enhancement is one of the major roadblock for SERS applications. Present study provides an effective way to enhance the site predictability for optimal SERS in addition to a significant enhancement in signal strength.