Fabrication of TiN–Ag@Ag Composite Substrate with SERS Performance and Application in Ibuprofen Detection

TiN–Ag@Ag composite substrates were prepared via ammonia reduction nitridation followed by electrochemical deposition. Fabricated TiN–Ag@Ag substrates were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and ultraviolet-visible spectrophotometry. The surface-enhanced Raman spectroscopy activity of these substrates was evaluated using ibuprofen as the probe molecule. The size of the Ag particles prepared via electrochemical deposition was approximately 1 μm, and Ag nanoparticles with an average particle size of 100 nm were uniformly distributed on the surface of TiN–Ag films. The Raman signal of ibuprofen was significantly enhanced, and the minimum detection concentration of ibuprofen was 10^–5 M. The mechanism by which the TiN–Ag@Ag composite substrate enhanced the Raman signals was analyzed using ultraviolet photoelectron spectroscopy and density functional theory implemented in the Gaussian software. Overall, charge transfer and the local electromagnetic field effect enhanced the Raman signals of ibuprofen.