Ogawa Daisuke, Nishina Yuta, Sano Koki
Department of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano, 386-8567, Japan.
Research Institute for Interdisciplinary Science, Okayama University, 3-1-1 Tsushimanaka, Kita-ku, Okayama, 700-8530, Japan.
Chempluschem. 2024 Dec;89(12):e202400449. doi: 10.1002/cplu.202400449. Epub 2024 Oct 18.
A magnetically responsive photonic crystal of colloidal nanosheets can exhibit a controllable structural color, offering diverse potential applications. In this study, we systematically investigated how the lateral sizes of graphene oxide (GO) nanosheets affect their magnetic responsiveness in a photonic system. Contrary to the prediction that larger lateral sizes of nanosheets would be more responsive to an applied magnetic field based on the magnetic energy of anisotropic materials, we discovered that GO nanosheets with larger lateral sizes in the photonic system scarcely responded to a 12 T magnetic field. The lack of magnetic response may be due to the strongly restricted rotational motion of GO nanosheets by mutual electrostatic forces. In contrast, GO nanosheets with medium lateral sizes readily responded to the 12 T magnetic field, forming a uniaxially oriented structure that resulted in a vivid structural color. However, smaller GO nanosheets displayed a less vivid structural color, possibly because of less structural ordering of GO nanosheets. Finally, we found that the photonic crystal of GO nanosheets with optimized lateral sizes responded effectively to the 12 T magnetic field across various GO concentrations, resulting in a vivid and tunable structural color.
一种由胶体纳米片构成的磁响应光子晶体能够展现出可控的结构色，具有多种潜在应用。在本研究中，我们系统地研究了氧化石墨烯（GO）纳米片的横向尺寸如何影响其在光子系统中的磁响应性。与基于各向异性材料的磁能所做出的预测（即纳米片横向尺寸越大，对施加的磁场响应越强）相反，我们发现光子系统中横向尺寸较大的GO纳米片对12 T的磁场几乎没有响应。缺乏磁响应可能是由于GO纳米片受相互静电力的强烈限制而难以发生旋转运动。相比之下，中等横向尺寸的GO纳米片对12 T的磁场很容易产生响应，形成单轴取向结构，从而产生鲜明的结构色。然而，较小的GO纳米片呈现出的结构色较不鲜明，这可能是因为GO纳米片的结构有序性较低。最后，我们发现具有优化横向尺寸的GO纳米片光子晶体在不同的GO浓度下均能对12 T的磁场做出有效响应，从而产生鲜明且可调节的结构色。
