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Abstract Diatom exoskeletons, known as frustules, exhibit a unique multilayer structure that has attracted considerable attention across interdisciplinary research fields as a source of biomorphic inspiration. These frustules possess a hierarchical porous structure, ranging from millimeter‐scale foramen pores to nanometer‐scale cribellum pores. In this study, this natural template for nanopattern design is leveraged to showcase metamaterials that integrates perfect absorption and subwavelength color printing. The cribellum‐inspired hierarchical nanopatterns, organized in a hexagonal unit cell with a periodicity of 300 nm, are realized through a single‐step electron beam lithography process. By employing numerical models, it is uncovered that an additional induced collective dipole mode is the key mechanism responsible for achieving outstanding performance in absorption, reaching up to 99%. Analysis of the hierarchical organization reveals that variations in nanoparticle diameter and inter‐unit‐cell distance lead to shifts and broadening of the resonance peaks. It is also demonstrated that the hierarchical nanopatterns are capable of color reproduction with high uniformity and fidelity, serving as hexagonal pixels for high‐resolution color printing. These cribellum‐inspired metamaterials offer a novel approach to multifunctional metamaterial design, presenting aesthetic potential applications in the development of robotics and wearable electronic devices, such as smart skin or surface coatings integrated with energy harvesting functionalities. 

Abstract Diatoms are photosynthetic algae that exist ubiquitously throughout the planet in water environments. Over the preceding decades, the diatom exoskeletons, termed frustules, featuring abundant micro‐ and nanopores, have served as the source material and inspiration for myriad research efforts. In this work, it is demonstrated that frustule‐inspired hierarchical nanostructure designs may be utilized in the fabrication of metamaterial absorbers, thereby realizing a broadband infrared (IR) absorber with excellent performance in terms of absorption. In an effort to investigate the origin of this absorption characteristic, numerical models are developed to study these structures, revealing that the hierarchical organization of the constituent nanoparticulate metamaterial unit cells introduce an additional resonance mode to the device, broadening the absorption spectrum. It is further demonstrated that the resonant peaks shift linearly as a function of inter‐unit‐cell spacing in the metamaterial, which is attributed to the induced collective dipole mode by the nanoparticles. Ultimately, the work herein represents an innovative perspective in terms of the design and fabrication of IR absorbers inspired by naturally occurring biomaterials, offering the potential to lead to advances in metamaterial absorber technology. 

Abstract Diatom frustules are a type of porous silicon dioxide microparticle that has long been used in applications ranging from biomedical sensors to dye‐sensitized solar cells. The favorable material properties, enormous surface area, and enhanced light scattering capacity support the promise of diatom frustules as candidates for next generation biomedical devices and energy applications. In this study, the vapor–liquid–solid (VLS) method is employed to incorporate silica nanowires on the surface of diatom frustules. Compared to the original frustule structures, the frustule–nanowire composite material's surface area increases over 3‐fold, and the light scattering ability increases by 10%. By varying the gold catalyst thickness during the VLS process, tuning of the resultant nanowire length/density is achieved. Through material characterization, it is determined that both float growth and root growth processes jointly result in the growth of the silica nanowires. From a thermodynamics point of view, the preferential growth of the silica nanowires on frustules is found to have resulted from the enormous partial surface area of gold nanoparticles on the diatom frustules. The frustule–nanowire composite materials have potential applications in the development of novel biomedical sensing devices and may greatly enhance next generation solar cell performance. 

Diatom Cribellum-Inspired Hierarchical Metamaterials The cribellum layer of diatom skeleton, termed frustule, features a hierarchical porous structure on the nanoscale. In article number 2403304 by Xin Zhang and co-workers, diatom cribellum inspired hierarchical metamaterials are presented to integrate the perfect absorption and subwavelength color printing. These diatom cribellum-inspired metamaterials offer a fresh perspective on multifunctional metamaterial design, promising scalability production by utilizing the frustule as a template for nanopatterning or bio-template synthesis.