Structural Color Materials with Color Mixing Effect Using Noble Metal‐Free Plasmonic Particles in SiO₂–ZrN System

Structurally colored materials with a color mixing effect are developed using SiO 2 –ZrN core–shell particles, where ZrN nanoparticles used as shells exhibited localized surface plasmon resonances (LSPRs). ZrN nanoparticles (10–30 nm) are attached to monodispersed SiO 2 particles by modifying SiO 2 particles with polymers. The attached ZrN nanoparticles exhibited a plasmon resonance absorption band at 700 nm. These SiO 2 –ZrN core–shell particles have a highly monodisperse particle size and assemble into a particle‐stacked film with Bragg diffraction light in the visible spectrum. The particle‐stacked film of the SiO 2 –ZrN core–shell particles exhibited the maximum reflection depending on the particle size of the SiO 2 core. The ratio of the reflection intensity in the long‐wavelength region corresponding to the ZrN absorption to that in the short‐wavelength region of the particle‐stacked film containing the ZrN shell is less than that of the ratio in only SiO 2 particle‐stacked film. The results reveal that these particle‐stacked films exhibit a “color mixing effect” that combines specific wavelength absorption through plasmon resonance and specific wavelength diffraction owing to the periodic structure without using precious metals.