Amorphous photonic structures with high reflective index based on incorporating Fe3O4@SiO2 core/shell colloidal nanoparticles into silica nanospheres

Amorphous photonic structures (APSs) with non-iridescent, non-fading, vivid structural colors have attracted great attention in several fields. Tremendous efforts have been dedicated to developing the effective and low-cost approaches for APSs with full-color displays. Resulting from the isotropic photonic pseudogap, APSs have non-iridescent structural colors. We demonstrate that incorporating F e 3 O 4 @ Si O 2 black nanoparticles into the interspace of the periodically arranged Si O 2 white nanospheres can synthesize APSs with different colors. The addition of F e 3 O 4 @ Si O 2 black nanoparticles can enhance the saturation of the non-iridescent structural colors of the APSs by reducing the incoherent scattering in the visible spectrum. In this case, different non-iridescent colors originate from the different diameters of the Si O 2 white nanospheres, and we obtained red, orange, yellow, green, and purple APSs with high reflective index successfully. The APSs with different colors may have potential applications in coatings, cosmetics, textiles, and displays. Moreover, as we use F e 3 O 4 @ Si O 2 as the additive, APSs can be recycled through its magnetic property.