基于六边形磁纳米片构建动态非晶态光学结构图案

Hexagonal Fe₂O₃ nanosheets were firstly prepared by a high-temperature solvothermal method. Then，a modified Stöber method was employed to coat Fe₂O₃ nanosheet with a SiO₂ shell，following with a gas-phase reduction method for the preparation of the monodisperse hexagonal Fe@SiO₂ nanosheet （FeNSs）. The obtained FeNS with the total side thickness of 220 nm and the total diagonal length of 400 nm has the advantages of uniform sizes，good dispersity and anisotropy. Notably，the FeNS was ferromagnetic with the saturation magnetization of 25.7 A·m²·kg⁻¹. Serving as building blocks，FeNSs assembled to a novel amorphous photonic structure （APS） under the synergistic effect of the magnetically induced force，evaporation-induced capillary force and mechanical force. By tuning the angle of magnetic fields from 0° to 80°and 90° （relative to the plane of substrates），the chromatic APS patterns with red，green and purple was obtained，respectively. From the characterization of SEM and FFT，it is demonstrated that the assembly of APS is mainly attributed to the magnetically induced control of the long axis of FeNSs. Additionally，by using the dependence of the structural color of APS on the magnetic field orientation，various APS patterns with dynamic structural colors were also obtained.