Tunable Dipole Surface Plasmon Resonances of Silver Nanoparticles by Cladding Dielectric Layers.
Tunable Dipole Surface Plasmon Resonances of Silver Nanoparticles by Cladding Dielectric Layers.
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通过包覆介电层可调谐银纳米颗粒的偶极表面等离子体共振
DOI：
10.1038/srep12555
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发表时间：
2015-07-28
影响因子：
4.6
通讯作者：
Chen Y
中科院分区：
文献类型：
--
作者：
Liu X;Li D;Sun X;Li Z;Song H;Jiang H;Chen Y
基于发射或吸收波长，表面等离子体共振的可调谐性可以使得能够实现最高程度的局部表面等离子体增强。在这篇文章中，可调偶极子表面等离子体共振的银纳米粒子（NPs）的实现通过修改的SiO2介电层的厚度。SiO2层的银纳米粒子的表面等离子体激元（LSP）的共振波长的影响。通过将Ag纳米颗粒下方的SiO2厚度从5 nm调整到20 nm，偶极表面等离子体共振从470 nm移动到410 nm。同时，在纳米颗粒制造之前通过生长SiO2来包覆Ag纳米颗粒，然后用从5 nm到20 nm的各种SiO2厚度包覆纳米颗粒之后，偶极表面等离子体共振从450 nm变化到490 nm。SiO2包覆的电介质层可以调节Ag NP表面电荷，导致周围介质的有效介电常数的变化，从而导致谐振波长的蓝移或红移。此外，四极等离子体共振被抑制的SiO2包覆层，因为介电SiO2可以抑制由Ag NP耦合效应引起的表面等离子体共振的能级分裂。
The tunability of surface plasmon resonance can enable the highest degree of localised surface plasmon enhancement to be achieved, based on the emitting or absorbing wavelength. In this article, tunable dipole surface plasmon resonances of Ag nanoparticles (NPs) are realized by modification of the SiO2dielectric layer thicknesses. SiO2layers both beneath and over the Ag NPs affected the resonance wavelengths of local surface plasmons (LSPs). By adjusting the SiO2thickness beneath the Ag NPs from 5 nm to 20 nm, the dipole surface plasmon resonances shifted from 470 nm to 410 nm. Meanwhile, after sandwiching the Ag NPs by growing SiO2before NPs fabrication and then overcoating the NPs with various SiO2thicknesses from 5 nm to 20 nm, the dipole surface plasmon resonances changed from 450 nm to 490 nm. The SiO2cladding dielectric layer can tune the Ag NP surface charge, leading to a change in the effective permittivity of the surrounding medium and thus to a blueshift or redshift of the resonance wavelength. Also, the quadrupole plasmon resonances were suppressed by the SiO2cladding layer because the dielectric SiO2can suppress level splitting of surface plasmon resonances caused by the Ag NP coupling effect.