Synthesis of ZrN-SiO2 core-shell particles by a sol-gel process and use as particle-based structured coloring material

ZrN-SiO2 core-shell particles were prepared, where the ZrN core nanoparticles and SiO2 shell were designed to exhibit localized surface plasmon resonances (LSPRs) and structural coloring. The heating of ZrO2 nanoparticles with Mg3N2 under a nitrogen gas flow produced ZrN nanoparticles with a diameter in the range of 10-20 nm. The dispersion of ZrN nanoparticles in water exhibited an absorption maximum at approximately 700 nm owing to LSPRs. An SiO2 shell was formed on the ZrN nanoparticles using a sol-gel process. Scanning transmission electron microscopy confirmed the formation of ZrN-SiO2 core-shell particles containing ZrN particles with a diameter of approximately 10 nm. The SiO2 shell thickness was controlled by varying the reaction time to form SiO2. The use of particles as a structural component of a structural color material owing to the high uniformity of the size of obtained core-shell particles was investigated. The obtained ZrN-SiO2 core-shell particles were arrayed on a glass substrate using a layer-by-layer method. The particle-stacked film of the ZrN-SiO2 core-shell particles exhibited the maximum reflection depending on the particle size of the SiO2 shell.