Colloidal Photonic Crystals toward Structural Color Palettes for Security Materials
Colloidal Photonic Crystals toward Structural Color Palettes for Security Materials
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DOI：
10.1021/cm4012603
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发表时间：
2013-07-09
影响因子：
8.6
通讯作者：
Kim, Shin-Hyun
中科院分区：
文献类型：
--
作者：
Lee, Hye Soo;Shim, Tae Soup;Kim, Shin-Hyun
单分散胶体粒子自组装成规则晶格为光子晶体的制备提供了相对简单和经济的方法。胶体晶体的光子阻带表现为乳白色结构色，这在显示器件、比色传感器和光学滤波器等方面具有潜在的应用价值。然而，胶体晶体具有低的耐久性，并且不期望的光散射使得结构为白色且半透明。此外，胶体晶体的微图案化通常需要复杂的成型过程，从而限制了它们的实际应用。为了克服这些缺点，我们开发了一种实用的和顺从的方法来制备胶体光子晶体具有高的光学透明度和物理刚性使用光固化胶体悬浮液。分散在可光固化介质中的胶体颗粒在毛细力诱导的渗透到板中期间结晶，并且随后介质的光聚合永久地固化结构。此外，常规的光刻能够实现晶体结构的微图案化。颗粒和基质之间的低折射率对比度导致所得复合结构的高透明度和窄反射峰，从而能够通过胶体晶体的不同层的重叠进行结构颜色混合。光谱中的多个窄峰在光学识别中提供高选择性，从而潜在地用于安全材料。
Self-assembly of monodisperse colloidal particles into regular lattices has provided relatively simple and economical methods to prepare photonic crystals. The photonic stop band of colloidal crystals appears as opalescent structural colors, which are potentially useful for display devices, colorimetric sensors, and optical filters. However, colloidal crystals have low durability, and an undesired scattering of light makes the structures white and translucent. Moreover, micropatterning of colloidal crystals usually requires complex molding procedures, thereby limiting their practical applications. To overcome such shortcomings, we develop a pragmatic and amenable method to prepare colloidal photonic crystals with high optical transparency and physical rigidity using photocurable colloidal suspensions. The colloidal particles dispersed in a photocurable medium crystallized during capillary force-induced infiltration into a slab, and subsequent photopolymerization of the medium permanently solidifies the structures. Furthermore, conventional photolithography enables micropatterning of the crystal structures. The low index contrast between particles and matrix results in high transparency of the resultant composite structures and narrow reflection peaks, thereby enabling structural color mixing through the overlapping of distinct layers of the colloidal crystals. Multiple narrow peaks in the spectrum provide high selectivity in optical identification, thereby being potentially useful for security materials.