论文期刊

Local dielectric environment-dependent plasmonic optical sensitivity of gold nanocage: from nanobox to nanoframe




作者: Jian Zhu1  · Jiang‑Kuan Chen1  · Jian‑Jun Li1  · Jun‑Wu Zhao1
发表/完成日期: 2019-01-02
期刊名称: Applied Physics A
期卷:
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论文简介
In this study, a gold nanobox with 40 nm edge length has been transformed into nanoframe gradually by increasing the
square-hole length in each {100} facet of the hexahedron. The local dielectric environment-dependent plasmon spectra and
refractive index sensitivity of this face-holed single gold nanocage were investigated based on the discrete dipole approximation method. Both the redshift of the resonance peak position and the sensitivity factor increased near exponentially with
increasing hole length, which could be attributed to the changing of hot regions of plasmonic field coupling. Moreover, the
shift of their resonance peak position to the refractive index of environmental medium increased linearly, and the face-holed
nanocage-based sensor shows an excellent sensitivity factor of 955.7 nm/RIU [figure of merit (FOM)=3.58]. It was also
noticed that the non-monotonic transform of the local field enhancement factor (|E/E0|) with a maximum of 80.9 is also
extremely affected by the refractive index. The physical mechanism discussed herein may be that the polarized field in local
dielectric environment becomes intense as the refractive index increases, resulting in an improvement of field enhancement
factor on the corners. We therefore believe that the square-hole length of {100} facets could enhance the plasmonic optical
sensitivity of nanocage-based nanoparticles.