Far-field, near-field and photothermal response of plasmonic twinned magnesium nanostructures
Far-field, near-field and photothermal response of plasmonic twinned magnesium nanostructures
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DOI：
10.1039/d3nr05848d
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发表时间：
2024-01-31
期刊：
影响因子：
6.7
通讯作者：
Ringe，Emilie
中科院分区：
文献类型：
--
作者：
Boukouvala，Christina;West，Claire A.;Ringe，Emilie
镁纳米粒子提供了另一种等离子体平台，能够在紫外、可见光和近红外波段产生共振。晶体镁纳米颗粒在（101）、（102）、（103）和（111）平面上显示孪生，导致凹折叠形状，分别称为帐篷、椅子、玉米饼和风筝。我们使用基于wulff的Crystal Creator工具在已知的Mg孪晶平面（即（10x）， x = 1,2,3和（11y）， y = 1,2,3,4）上扩展具有孪晶的Mg晶体形状的范围，并研究相对facet表达式对所得形状的影响。这些形状包括凹结构和凸结构，其中一些已经在实验中观察到。报道了这些不寻常的等离子体形状的共振模式、远场和近场光学响应以及它们的光热行为，揭示了折叠角度和凹区填充的影响。不同形状之间存在显著差异，特别是在最大电场增强和平均电场增强方面。在（114）风筝的尖端，发现了184的最大场增强（|E|/|E0|），与Au和Ag纳米颗粒的计算结果相当。研究发现，5nm MgO壳层的存在使近场增强降低了67% ~ 90%，这取决于其形状，而它可以使等离子体激元诱导的温度升高高达42%。尖端的圆角也会显著影响最大场增强。这些结果为在宽光谱范围内各种等离子体应用的增强和光热衬底的设计提供了指导。
Magnesium nanoparticles offer an alternative plasmonic platform capable of resonances across the ultraviolet, visible and near-infrared. Crystalline magnesium nanoparticles display twinning on the (101), (102), (103), and (111) planes leading to concave folded shapes named tents, chairs, tacos, and kites, respectively. We use the Wulff-based Crystal Creator tool to expand the range of Mg crystal shapes with twinning over the known Mg twin planes, i.e., (10x), x = 1, 2, 3 and (11y), y = 1, 2, 3, 4, and study the effects of relative facet expression on the resulting shapes. These shapes include both concave and convex structures, some of which have been experimentally observed. The resonant modes, far-field, and near-field optical responses of these unusual plasmonic shapes as well as their photothermal behaviour are reported, revealing the effects of folding angle and in-filling of the concave region. Significant differences exist between shapes, in particular regarding the maximum and average electric field enhancement. A maximum field enhancement (|E|/|E0|) of 184, comparable to that calculated for Au and Ag nanoparticles, was found at the tips of the (114) kite. The presence of a 5 nm MgO shell is found to decrease the near-field enhancement by 67% to 90% depending on the shape, while it can increase the plasmon-induced temperature rise by up to 42%. Tip rounding on the otherwise sharp nanoparticle corners also significantly affects the maximum field enhancement. These results provide guidance for the design of enhancing and photothermal substrates for a variety of plasmonic applications across a wide spectral range.