Silver nanoparticles deposited inverse opal film as a highly active and uniform SERS substrate

Ag-decorated TiO2 inverse opal films (ATIO) with high surface-enhanced Raman scattering (SERS) enhancement were prepared using an electroless deposition process. The Ag nanoparticles (NPs) are well-dispersed and deposited on the edge of macroporous walls. The structure and optical properties of the sample ATIO have been characterized. The Ag-loading cycles and pore sizes of TiO2 inverse opal are the key factors determining the magnitude of SERS signal enhancement. The optimized ATIO samples exhibit high SERS signal enhancement ability and reproducibility. The enhancement factor about 104 and the detection limit of 10−10 M for R6G were achieved. The further application in detecting malachite green is demonstrated. A limit of detection approximately 10−9 M was achieved. The results show that the ATIO nanostructure is promising for using as sensor substrates in SERS applications.