Fabrication and characterization of structurally colored pigments based on carbon-modified ZnS nanospheres

Chemical pigments are widely used in various industries. Most of those produced from organic or inorganic chemicals easily fade over time or upon exposure to light. Recently, vivid structurally colored pigments with a non-iridescent character produced from APSs (amorphous photonic structures) have attracted great attention. However, the generally used non-iridescent structural coloration pigments produced from a mixture of colloidal spheres and carbon black in tens of nanometers are not stable because nanosized carbon black with high surface energy reunites together easily, often leading to nonuniform distribution and significant decrease in brightness. In this work, we report non-iridescent, structurally colored pigments assembled by carbon-modified ZnS nanospheres. Compared with the conventional method, the pigments prepared in our work show uniform carbon distribution and low angle dependence. Moreover, the refractive index of ZnS is higher than the generally used SiO2 and PS. Typical paints prepared by a mixture of colored pigments with ethanol could be spray-coated on any substrate without limitation. Structural coloration pigments based on carbon-modified ZnS nanospheres with low angle dependence, uniform carbon distribution and enhanced color saturation have promising applications in the fields of nontoxic and non-bleaching pigments.