Infiltration-assisted colloidal assembly of amorphous photonic crystal patterns with high color saturation and mechanical stability

Abstract

Amorphous photonic crystals (APCs) can display noniridescent structural colors because of their short-range ordered arrangement of monodisperse nanospheres. However, the APCs suffer from low color saturation and poor mechanical stability, which restricts their widespread applications. In this work, monodisperse brown polysulfide (PSF) nanospheres with tunable sizes were used as building blocks and cross-linkable polyacrylate (CLPA) nanoparticles were employed as nanoadhesives for the construction of vivid amorphous photonic crystal (APC) patterns with high mechanical stability. Due to the high refractive index (RI) and light-absorbing characteristics of PSF building blocks, the multiple incoherent light scattering inside APCs was greatly suppressed, resulting in noniridescent structural colors with high color saturation. Besides, the embedding of CLPA nanoparticles within the interspaces of PSF building blocks facilitated tight bonding between neighboring PSF particles or particles and substrates, effectively enhancing the mechanical stability of the APCs. The effects of PSF nanosphere size or CLPA nanoparticle content were investigated in detail in order to achieve the best structural color quality or mechanical stability of APCs, and the optimized APC samples displayed vivid colorful colors and rendered excellent resistance towards mechanical scratches. We believe that the infiltration-assisted (IFAST) colloidal assembly of brown high-RI particles together with nanoadhesives opens an avenue towards rational design and scalable manufacturing of full-spectrum APC patterns with high color quality for practical applications.