The improvements on TiO2 catalyzed AgNPs based SERS substrate and detection methods

Using TiO2 on slides to facilitate photo-catalysis of silver nano-particles (AgNPs) is a simple and versatile way of making silver based solid SERS substrates. However, due to the difficulty of getting optimal surface AgNPs structure, it is difficult to reach optimal enhancement factor or measurement uniformity with this method. In this research, production conditions and setups, ranging from dip-coating to photo-catalysis are investigated. Spectral analysis show that some conditions, such as time of calcination and the purity of UV light used in photo-catalysis, affect the resulting SERS substrates more significantly. The overall performance of substrates made using this method is increased; sensitivity is increased so that the limit of detection for Rhodamin 6G (R6G) is as low as 10−8 M, and the signature peak of R6G at 1650 cm−1 measured from different spots on substrates has a standard deviation of less than 20%.