Surface-enhanced raman scattering properties of Au@TiO2 plasma exciton array structures

Abstract

Surface Enhanced Raman Scattering (SERS) is an ultrasensitive spectroscopic analysis technique widely used for molecular detection. SERS is characterized by rapid analysis, trace detection, ultra-high sensitivity, non-destructive, etc., and can analyze the concentration, composition, and structure of the detected substances. It has a significant potential for application in many fields, such as biomedicine, trace detection, food safety, and environmental protection. However, fabrication of homogeneous, stable, and ultrasensitive SERS substrates remains a challenge for the practical application of SERS technology. Precious metals and semiconductors have been proven attractive and versatile for SERS detection. In this work, three-dimensional Au@TiO2 substrates were prepared using a facile strategy, and two different types of Raman probe molecules were used to demonstrate the versatility of the design. Using 4-MBA as the probe molecule, the enhancement factor of the TiO2 substrate could reach 1.52×104, and the detection limit was as low as 10-16 M. The results indicate that the Au@TiO2 substrate is simple to prepare, inexpensive, and serves as an excellent SERS substrate structure. 4-MBA and R6G dual probe molecules demonstrate the universality of the Au@TiO2 nanocavity array structure. In the meantime, the results of the simulations match the experimental results. It also demonstrates that the three-dimensional Au@TiO2 has the potential to be an excellent SERS substrate.