TiO2 Thickness-Dependent Charge Transfer in an Ordered Ag/TiO2/Ni Nanopillar Arrays Based on Surface-Enhanced Raman Scattering

In this study, an ordered Ag/TiO2/Ni nanopillar arrays hybrid substrate was designed, and the charge transfer (CT) process at the metal-semiconductor and substrate-molecule interface was investigated based on the surface-enhanced Raman scattering (SERS) spectra of 4-Aminothiophenol (PATP) absorbed on the composite system. The surface plasmon resonance (SPR) absorption of Ag changes due to the regulation of TiO2 thickness, which leads to different degrees of CT enhancement in the system. The CT degree of SERS spectra obtained at different excitation wavelengths was calculated to study the contribution of CT enhancement to SERS, and a TiO2 thickness-dependent CT enhancement mechanism was proposed. Furthermore, Ag/TiO2/Ni nanopillar arrays possessed favorable detection ability and uniformity, which has potential as a SERS-active substrate.

Automated summary

This study designed an ordered Ag/TiO2/Ni nanopillar arrays hybrid substrate and investigated the charge transfer process at the metal-semiconductor and substrate-molecule interface. The contribution of charge transfer enhancement to surface-enhanced Raman scattering (SERS) was determined by calculating the CT degree of the obtained SERS spectra, and a thickness-dependent CT enhancement mechanism was proposed.