Manufacturing of nanoestructures by laser ablation and its use in SERS with low detection threshold: the case of Ag-NPs

Abstract

In this work we present the manufacture of silver nanoparticles (Ag-NPs) by means of laser ablation (AL) in aqueous medium, and its application as elements of Raman signal enhancement through SERS type processes. This methodology allows to obtain stable suspensions of NPs free of the use of chemical processes, with dispersions of relatively small sizes and of easy processing for the implementation of SERS substrates of silica. Through the use of aliquots at different concentrations of Rhodamine 6G (R6G), it is demonstrated that with these Ag-NPs, Raman signal detection thresholds are reached in concentrations of the order of nM. The study of the distribution of Ag-NPs on a silica substrate was carried out by atomic force microscopy (AFM). In turn, some simulation results of the magnitude of the fields are generating hot spot in specific regions of the Ag-NPs taking into account the morphology of some of the agglomerates identified in the electron scanning microscopy (SEM) in the SERS substrates. In comparison to some previous reports, the present work demonstrates low detection thresholds and simple implementation in SERS substrates.