Shell-isolated nanoparticle-enhanced Raman spectroscopy.
(A) TEM images of Au/SiO2 core-shell nanoparticles with different shell thicknesses. (B) Schematic of the sensing principle. Shell-isolated nanoparticles can be used to probe any surface or morphology. (C) Schematic of a SHINERS experiment for the detection of pesticides on citrus fruits. (D) Normal Raman and SHINERS spectra for oranges with and without pesticide contamination by parathion (A–D adapted by permission from Macmillan Publishers Ltd: Nature , copyright 2010). (E) TEM images of Au/PAT core-shell nanoparticles with different shell thicknesses (F) SERS spectra of Au@2 nm PAT NPs + TNT (10-2 m to 10-5 m) (E–F reprinted from . Reproduced by permission of The Royal Society of Chemistry). (G, H) SEM images and extinction spectra of Au NRs with different aspect ratios prepared by tuning the volumes of the Au seed solution (G–H reprinted with permission from . Copyright 2013, John Wiley & Sons, Ltd.).