Spectroscopic properties of multilayered gold nanoparticle 2D sheets.
Spectroscopic properties of multilayered gold nanoparticle 2D sheets.
复制标题
多层金纳米粒子二维片的光谱特性。
作者：
Akihito Yoshida;K. Imazu;Xinheng Li;K. Okamoto;K. Tamada
我们报告了多层二维（2D）金纳米颗粒片（“Au 纳米片”）的制造技术和光学特性。由 Au 纳米粒子组成的 2D 晶体单层片显示出源自局域表面等离子体共振 (LSPR) 的吸收峰。研究发现，当单层在不同基底（石英或金）上组装成多层时，吸收光谱会发生巨大变化。对于金薄膜上的多层膜（d = 200 nm），通过增加层数，局域表面等离子体共振峰值在近红外区域移动到更长的波长。吸光度还取决于层数并显示非线性行为。另一方面，石英基底上的多层膜既没有表现出局域表面等离子体共振峰值漂移，也没有表现出吸光度的非线性响应。正如我们之前的研究中所提出的，金属表面的层数依赖性可以解释为局域表面等离子体共振的近场耦合和分层超材料薄膜的远场光学之间的综合效应。我们还报告了由两种单层（即金纳米片和银纳米片）组成的混合多层膜的光谱特性。不同金属纳米颗粒片的组合实现了更灵活的等离子体颜色调节。
We report the fabrication technique and optical properties of multilayered two-dimensional (2D) gold nanoparticle sheets ("Au nanosheet"). The 2D crystalline monolayer sheet composed of Au nanoparticles shows an absorption peak originating from a localized surface plasmon resonance (LSPR). It was found that the absorption spectra dramatically change when the monolayers are assembled into the multilayers on different substrates (quartz or Au). In the case of the multilayers on Au thin film (d = 200 nm), the LSPR peak is shifted to longer wavelength at the near-IR region by increasing the number of layers. The absorbance also depends on the layer number and shows the nonlinear behavior. On the other hand, the multilayers on quartz substrate show neither such LSPR peak shift nor nonlinear response of absorbance. The layer number dependence on metal surfaces can be interpreted as the combined effects between the near-field coupling of the LSPR and the far-field optics of the stratified metamaterial films, as proposed in our previous study. We also report the spectroscopic properties of hybrid multilayers composed of two kinds of monolayers, i.e., Au nanosheet and Ag nanosheet. The combination of the different metal nanoparticle sheets realizes more flexible plasmonic color tuning.