Okazaki Takuma, Sugimoto Hiroshi, Hinamoto Tatsuki, Fujii Minoru
Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, Rokkodai, Nada, Kobe 657-8501, Japan.
JST-PRESTO, Honcho 4-1-8, Kawaguchi, Saitama 332-0012, Japan.
ACS Appl Mater Interfaces. 2021 Mar 24;13(11):13613-13619. doi: 10.1021/acsami.1c01692. Epub 2021 Mar 10.
An ink of silicon nanoparticles (Si NPs) having the lowest-order Mie resonance in the visible range can generate noniridescent and nonfading structural colors in a wide area through a painting process. However, the strong wavelength dependence of the radiation pattern and the extinction coefficient make the multiple reflection behavior very complicated, and thus, a reliable tool is necessary to predict the hue, saturation, and brightness of the reflection color. In this work, a Monte Carlo simulation to predict the reflection color of Si NP inks is first developed. The simulation takes into account the scattering and absorption cross-sections, a radiation pattern of an individual NP, and multiple scattering in NP dispersion. The simulation shows that the reflection color of a Si NP ink depends strongly on the concentration because of the wavelength dependence of the multiple scattering behavior. To extend the controllable range of the hue, saturation, and brightness of Si NP inks, a mixture ink with light-absorbing carbon black (CB) NPs is developed. It is experimentally demonstrated that the combination of the Kerker-type back scattering of a Si NP and a broad absorption by a CB NP allows us to control the hue, saturation, and brightness in a wide range and to realize vivid reflection colors under room light.
一种在可见光范围内具有最低阶米氏共振的硅纳米颗粒（Si NPs）墨水，可通过涂覆工艺在大面积上产生非虹彩且不褪色的结构色。然而，辐射模式和消光系数对波长的强烈依赖性使得多次反射行为非常复杂，因此，需要一个可靠的工具来预测反射颜色的色调、饱和度和亮度。在这项工作中，首先开发了一种用于预测Si NP墨水反射颜色的蒙特卡罗模拟。该模拟考虑了散射和吸收截面、单个NP的辐射模式以及NP分散体中的多次散射。模拟表明，由于多次散射行为对波长的依赖性，Si NP墨水的反射颜色强烈依赖于浓度。为了扩大Si NP墨水色调、饱和度和亮度的可控范围，开发了一种含有吸光炭黑（CB）NP的混合墨水。实验证明，Si NP的Kerker型后向散射与CB NP的广泛吸收相结合，使我们能够在很宽的范围内控制色调、饱和度和亮度，并在室内光线下实现鲜艳的反射颜色。
