Porous silicon decorated with Au/TiO₂ nanocomposites for efficient photoinduced enhanced Raman spectroscopy

In this study, we investigated the potential of porous silicon (PSi) modified with Au/TiO₂ nanocomposites (NCPs) as a substrate for photoinduced enhanced Raman spectroscopy (PIERS). One-step pulsed laser-induced photolysis (PLIP) was used to embed Au/TiO₂ NCPs in the surface of PSi. Scanning electron microscopy revealed that adding TiO₂ nanoparticles (NPs) during PLIP led to the formation of predominantly spherical Au NPs with a diameter of approximately 20 nm. Furthermore, modifying the PSi substrate with Au/TiO₂ NCPs considerably enhanced the Raman signal of rhodamine 6G (R6G) after 4 h of ultraviolet (UV) irradiation. Real-time monitoring of the Raman signals of R6G at different concentrations under UV irradiation revealed that the amplitude of the signals increased with the irradiation time for R6G concentrations ranging from 10^-3 M to 10^-5 M. PSi substrates decorated with Au/TiO₂ NCPs may be used to develop materials for PIERS applications.