Abstract
Amorphous photonic structures (APSs) with short-range ordered arrangement have attracted great interest because of their wide view angles. However, the presented methods for the APSs color printing and 3D coating on different substrates and curvatures are lack of control. Here, APSs with angle-independent structural colors were fabricated by the self-assembly of SiO2@Fe3O4 core-shell nanostructures, which were prepared by the hydrolysis of Fe(acac)3 on the silica surfaces. The size of SiO2@Fe3O4 core-shell colloids can be controlled well through the tuning of SiO2 particle size, whereas the coverage of Fe3O4 on silica surfaces can be precisely tailored through altering the mass ratio between Fe3O4 precursor and SiO2. APSs with only short-range ordered structures, uniform noniridescent structural colors, and high color visibility can be obtained through the self-assembly of SiO2@Fe3O4 colloids of different particle sizes in a few minutes. They are mainly attributed to the weak electrostatic repulsion interactions between SiO2@Fe3O4 colloids because of the partial coverage of Fe3O4 on silica surfaces and absorption of the incoherent multiple scattering of visible light from Fe3O4. Moreover, SiO2@Fe3O4 colloids show good adhesion to various substrates, such as paper, glass, plastics, resins, ceramics, and wood, which facilitates the formation of uniform APSs on different substrates. Multicolor prints and 3D coating of APSs on substrates with different curves and roughness can be realized on the basis of the fast assembly of SiO2@Fe3O4 colloids.