Ag-SiO2 Janus particles based highly active SERS macroscopic substrates

摘要

Macroscopic SERS (M-SERS) substrate with high activity was fabricated by attaching Ag-SiO2 Janus particles with similar to 3 nm sized silver nanoparticles (AgNPs) on a cellulosic film. The synthesized Ag-SiO2 Janus particles had in-situ deposited AgNPs on one-half and amine functionalization on the other-half, which was utilized for their fixation as a monolayer on cellulosic substrate. Ranian spectrum of Rhodamine B (RhB) showed an enhancement factor of similar to 5 x 10(4) for dye tagged on both Janus particles and M-SERS. In comparison, AgNPs with almost the same diameter, even after aggregation, did not show enhancement of Raman signals. The enhancement is attributed to in -situ reduction of silver precursor on the SiO2 surface leading to deposition of AgNPs and generation of a large number of fixed hot-spots in a controlled manner. The Janus particles and M-SERS with 3 nm sized AgNPs can find application as both SERS active as well as catalytic material. (C) 2017 Elsevier B.V. All rights reserved.