Liu Tianyu, Solomon Michael J
Department of Chemical Engineering and Biointerfaces Institute, University of Michigan, Ann Arbor, MI, 48109, USA.
Small. 2023 Sep;19(37):e2301871. doi: 10.1002/smll.202301871. Epub 2023 May 5.
Self-assembled colloidal crystals display structural colors due to light diffracted from their microscale, ordered structure. This color arises due to Bragg reflection (BR) or grating diffraction (GD); the latter mechanism is much less explored than the former. Here the design space for generating GD structural color is identified and its relative advantages are demonstrated. Electrophoretic deposition is used to self-assemble crystals with fine crystal grains from colloids of diameter 1.0 µm. The structural color in transmission is tunable across the full visible spectrum. The optimum optical response-represented by both color intensity and saturation-is observed at low layer number (≤5 layers). The spectral response is well predicted by Mie scattering of the crystals. Taken together, the experimental and theoretical results demonstrate that vivid grating colors with high color saturation can be produced from thin layers of micron-sized colloids. These colloidal crystals extend the potential of artificial structural color materials.
自组装胶体晶体由于从其微观尺度的有序结构衍射的光而呈现结构色。这种颜色是由布拉格反射（BR）或光栅衍射（GD）产生的；后一种机制的研究比前一种少得多。本文确定了产生GD结构色的设计空间，并展示了其相对优势。采用电泳沉积法自组装由直径为1.0 µm的胶体形成的具有细晶粒的晶体。透过率中的结构色在整个可见光谱范围内是可调的。在低层数（≤5层）时观察到由颜色强度和饱和度表示的最佳光学响应。通过晶体的米氏散射可以很好地预测光谱响应。综合实验和理论结果表明，微米级胶体的薄层可以产生具有高颜色饱和度的鲜艳光栅颜色。这些胶体晶体扩展了人工结构色材料的潜力。
