Plasmon mediated SERS and photocatalysis enhancement in Au nanoparticle decorated 2D-TiSe₂

The combination of 2D materials and noble metallic nanostructure is becoming an attractive research domain for label-free, highly sensitive surface-enhanced Raman spectroscopy (SERS) applications. This study demonstrated photocatalysis degradation and SERS enhancements of organic fluorophore (Rhodamine 6G) on two-dimensional (2D) TiSe₂using Raman spectroscopy. The Au nanoparticles (NPs) were decorated on TiSe₂thin films by thermal annealing at variable temperatures. The selective deposition of Au NPs on the hexagonal TiSe₂nanocrystals increases surface roughness, creating a larger surface area for molecule adsorption. It has been observed that the Au decoration at 250 °C on TiSe₂exhibits efficient detection capabilities for R6G with the Raman intensity enhancement factors of the order of ≈10⁵along with the significantly improved visible light-induced photodegradation efficiency. The optimized Au NP size creates large electromagnetic hot spots produced by strong plasmon coupling that assists in the charge transfer mechanism among TiSe₂, Au NPs, and R6G for enhanced SERS and photocatalysis activities. It has been observed that the intensity of Raman scattering decreases as the Au NP size increases on the TiSe₂material. A possible charge transfer mechanism is proposed with an energy band diagram. The simultaneous measurement of SERS and photocatalytic dye degradation in Au decorated TiSe₂can be used as a sensitive technique for water pollution treatment and biodegradable organic contaminants for the environmental ecosystem.