Hierarchical Hexagonal Boron Nitride Nanowall-Decorated Silicon Nanoparticles for Tunable Ink-Free Coloring

Nanomaterials with tunable optical properties have emerged as active components for advanced nanophotonic devices. Herein, the fabrication of hierarchical nanostructures through the integration of various tunable nanomaterials for diverse applications remains a challenge. Here, a two-step process consisting of the synthesis of silicon nanoparticles (Si NPs) via laser ablation followed by plasma-enhanced chemical vapor deposition of hexagonal-boron-nitride (h-BN) nanowalls has been implemented to form hierarchical Si@h-BN NPs. Experimental and numerical analyses confirm that h-BN decoration modulates the color and brightness of the hierarchical NPs (i.e., shape, intensity, and spectral width of intrinsic optical resonances). Moreover, the color palette of the resulting Si@h-BN NPs can be remotely controlled by infrared laser irradiation. We reveal that this control is related to the modification of the complex morphology of the hierarchical Si@h-BN NPs through the mutual influence of Si NP and h-BN on each other. These results open a way for utilizing hierarchical nanostructures for light manipulation at the nanometer scale for optical data storage and ink-free coloring.