Nho Hyun Woo, Yoon Tae Hyun
Department of Chemistry, College of Natural Sciences, Research Institute for Natural Sciences, Hanyang University, Seoul, 04762, Republic of Korea.
LG Chem R&D Campus Daejeon, Daejeon, 34122, Republic of Korea.
Sci Rep. 2017 Sep 29;7(1):12424. doi: 10.1038/s41598-017-12831-4.
Colloidal crystals composed of micro- or nano- colloids have been investigated in various fields such as photonics due to their unique optical properties. Binary colloidal crystals have an outstanding potential for fine-tuning material properties by changing the components, concentration, or size of colloids. Because of their tunable optical, electrical, magnetic, and mechanical properties, those materials attracted great attention. However, it has been hard to elucidate internal structures without fluorescent labelling or cross-sectioning. Here, we demonstrate the structural analysis of not only unary but also binary colloidal crystals using scanning transmission x-ray microscopy and compare the results with colloidal structures and optical properties observed by optical microscopy. Based on the comparison of images obtained by these two methods, the domains of colloidal crystals consisting of different structures and colours were directly identified without any additional sample preparation. Therefore, it was possible to investigate the structural colours of local domains of unary and binary colloidal crystals such as the face centred cubic (FCC) structure with different orientations, that is FCC (111) and FCC (001), and hexagonal close-packed structure, HCP (0001).
由微米或纳米胶体组成的胶体晶体因其独特的光学性质而在光子学等各个领域得到了研究。二元胶体晶体通过改变胶体的成分、浓度或尺寸来微调材料性能方面具有巨大潜力。由于其可调谐的光学、电学、磁学和力学性能，这些材料引起了极大关注。然而，在没有荧光标记或切片的情况下很难阐明其内部结构。在这里，我们展示了使用扫描透射X射线显微镜对一元和二元胶体晶体进行结构分析，并将结果与光学显微镜观察到的胶体结构和光学性质进行比较。基于这两种方法获得的图像比较，无需任何额外的样品制备即可直接识别由不同结构和颜色组成的胶体晶体区域。因此，有可能研究一元和二元胶体晶体局部区域的结构颜色，如具有不同取向的面心立方（FCC）结构，即FCC（111）和FCC（001），以及六方密堆积结构HCP（0001）。
