| 论文简介 |
We synthesized a novel bimetallic core–shell–satellite surface-enhanced Raman scattering (SERS)
substrate (AuNS@mSiO2@AgNP) that consists of a gold nanostar (AuNS) core, a mesoporous silica
(mSiO2) shell and a layer of silver nanosphere (AgNP) satellites. The core–shell–satellite nanostructure
was formed by growing branches in the mSiO2 shell of mSiO2 coated gold nanospheres (AuNP@mSiO2)
using AuNPs as the seeds, and the subsequent deposition of AgNPs on the mSiO2 surface. The growth
of AuNSs in mSiO2 leads to the formation of a large number of closely spaced branches which provide
enormous hotspots; and by varying the length of the branches, the nanogap distance between the AuNS
core and the AgNP satellites can be carefully adjusted. Besides, mSiO2 could allow the infiltration of the
analyte into the nanogap area that has high SERS enhancement. To demonstrate the feasibility of the
SERS substrate, the bimetallic core–shell–satellite nanostructures were used for the label-free detection
of a pesticide named thiram. The AuNS@mSiO2@AgNP was shown to have excellent selectivity and SERS
activity which is significantly higher than that of AuNS@mSiO2, mSiO2@AgNP and AuNP@mSiO2@AgNP.
This method exhibits a good linear response when the thiram concentration ranges from 109 M to
103 M, and the limit of detection (LOD) is 109 M, showing that the bimetallic core–shell–satellite
nanostructure is a promising SERS substrate. |
(创新港)
