Coloring control by nanoscale surface coarseness

某种纳米金属结构呈现出特有的颜色。众所周知，纳米尺寸的金颗粒呈现红色，很少有人知道它们呈现其他颜色。在本研究中，通过纳米级表面粗糙度进行着色控制，使用干燥方法生成了红色以外的蓝色或绿色结构。FE-SEM观察显示了纳米结构的精确形状。根据FE-SEM观测建立了三维计算模型。通过光学测量确定了等离子体吸收峰。通过电磁场计算，明确了金纳米结构的等离子体激元峰值波长是由其尺寸、形状和间距决定的。最后，纳米结构的颜色大致可以预期。这些结果可以通过控制纳米结构的尺寸、形状、数量、密度和覆盖范围等特性来实现LSPR器件的设计。

A certain kind of nano size metal structures reveals a characteristic color. It is known that the gold particles of nano size present red color, and it is seldom known that they present other colors. In this study blue or green colored structure other than red were generated using a dry method by performing coloring control using nano level surface roughness. FE-SEM observation revealed the precise shape of nanostructure. The 3-dimensional calculation models were constructed from the FE-SEM observation. Plasmon absorption peaks were identified by carrying out optical measurements. Through the electromagnetic field calculation it was clarified that the plasmon peak wavelength of gold nano structure was determined by its size, shape and spacing. Finally the color of the nano structure can be expected generally. These results may enable the design of LSPR devices by controlling the characteristics of the nanostructures, such as their size, shape, number density and coverage.