Nanopores limited domain and PVA film used to assist the SERS property of gold nanoparticle arrays

Abstract

The combination of nanopores and noble metal nanoparticles has been the focus of research in recent years, and their synergistic effect enabled the substrate exhibit excellent SERS property. In this paper, the array porous silicon structures embedded with gold nanoparticles have been prepared by using the polystyrene (PS) microsphere template assisted gold annealing process and metal assisted chemical etching techniques (AuNPs@nanopore). Polyvinyl alcohol (PVA) thin film was introduced as a molecular adsorption layer to be spin coated on the surface and formed composite structure (AuNPs@nanopore @PVA) to enrich more detection molecules. Through the SERS analysis of different depths of gold nanoparticles by Rhodamine 6G (R6G) probe molecules, the optimal etching time, that is, the optimal depth that gold nanoparticles should be in, was determined. Under the etching time of 2 min, the AuNPs@nanopore @PVA structure base with pore depth of 245 nm and diameter of gold nanoparticles of 181 nm showed high sensitivity, high uniformity and the best SERS property. It can realize the low concentration detection of 10−10 mol/L R6G molecule and 10−11 mol/L methylene blue (MB) molecule, and the enhancement factor is up to 1.20 × 107. The substrate can also be used to detect the pesticide thiabendazole molecule, the detection limit of 10−8 mol/L.