Abnormally Large Plasmonic Shifts in Silica-Protected Gold Triangular Nanoprisms
Abnormally Large Plasmonic Shifts in Silica-Protected Gold Triangular Nanoprisms
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DOI：
10.1021/jp911889a
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发表时间：
2010-04-29
影响因子：
3.7
通讯作者：
Mirkin, Chad A.
中科院分区：
文献类型：
--
作者：
Banholzer, Matthew J.;Harris, Nadine;Mirkin, Chad A.
报道了二氧化硅包裹的金纳米棱镜（AuNP@SiO2）的合成。这些纳米结构非常稳定，并且在许多化学环境（水，乙醇，二甲基亚砜和四氢呋喃）中抵抗蚀刻和其尖锐顶点的圆化（在几个小时内开始于未受保护的Au纳米棱镜的过程）。已经研究了二氧化硅生长过程，并且根据颗粒的形状发生，其中棱柱的边缘被涂覆的少于大的三角形小面。AuNP@SiO2颗粒具有高达737 nm/RIU的介电灵敏度。离散偶极近似计算已被用来研究这种可变厚度对介电灵敏度的影响，并表明，对于各向异性涂层，它是显着高于一个均匀的涂层，由于电磁热点的位置附近的尖端和边缘的颗粒。这些计算还表明，由于多极电磁场的范围较短，偶极共振比多极共振表现出更大的灵敏度。
The synthesis of silica-encapsulated gold nanoprisms (AuNP@SiO2) is reported. These nanostructures are remarkably stable and resist etching and rounding of their sharp vertices (a process which begins on unprotected Au nanoprisms in a matter of hours) in many chemical environments (water, ethanol, dimethyl sulfoxide, and tetrahydrofuran). The silica growth process has been studied and occurs according to the shape of the particle, where the edges of the prisms are coated less than the large triangular facets. The AuNP@SiO2 particles have dielectric sensitivities that are as large as 737 nm/RIU. Discrete dipole approximation calculations have been used to investigate the effects of this variable thickness on dielectric sensitivity and show that for the anisotropic coatings it is significantly higher than for a uniform coating due to the location of electromagnetic hot spots near the tips and edges of the particles. These calculations also show that dipole resonances exhibit greater sensitivity than multipole resonances, due to the shorter range of the multipolar electromagnetic fields.