Although various photonic devices inspired by natural materials have been developed, there is no research focusing on multibands adaptability, which is not conducive to the advancement of materials ...science. Herein, inspired by the moth eye surface model, state‐of‐the‐art hierarchical metamaterials (MMs) used as tunable devices in multispectral electromagnetic‐waves (EMWs) frequency range, from microwave to ultraviolet (UV), are designed and prepared. Experimentally, the robust broad bandwidth of microwave absorption greater than 90% (reflection loss (RL) < −10 dB) covering almost entire X and Ku bands (8.04–17.88 GHz) under a deep sub‐wavelength thickness (1 mm) is demonstrated. The infrared emissivity is reduced and does not affect the microwave absorption simultaneously, further realizing anti‐reflection and camouflage via the strong visible light scattering by the microstructure, and can prevent degradation by reducing the transmittance to less than 10% over the whole near UV band, as well as having hydrophobic abilities. The mechanism explored via simulation model is that topological effects are found in the bio‐structure. This discovery points to a pathway for using natural models to overcome physical limits of MMs and has promising prospect in novel photonic materials.
Inspired by the moth eye surface structure, state‐of‐the‐art hierarchical metamaterials with broadband absorption of microwaves are designed and prepared. The hierarchical metamaterials also demonstrate multibands adaptability. Microwave‐infrared compatible manipulation, anti‐reflection and color‐changing, ultraviolet shielding, and self‐cleaning are realized simultaneously, which have great potential application in the stealth and camouflage field.
Photoelectrochemical (PEC) water splitting, which harnesses solar radiation (an infinite energy source) for clean hydrogen production without carbon-dioxide emissions, is an ideal eco-friendly energy ...technology. The core reactions in PEC water splitting, involving the oxidation and reduction of water, are driven by electron–hole pairs generated through solar energy absorption. Consequently, the light-absorption efficiency emerges as a critical parameter in PEC devices. Conventional thin-film-type photoanodes, however, grapple with limited absorption due to their high reflectance, hindering absorption and carrier separation efficiency. Conversely, moth-eye-structured photoanodes exhibit an anti-reflection effect stemming from their subwavelength structure, markedly enhancing light-absorption efficiency. In this study, we present the design and fabrication of a densely packed moth-eye-structured bismuth vanadate (BiVO4) (M-BVO) photoanode, which is engineered to possess superior light absorption properties. The photoanode was fabricated via direct printing, electron-beam evaporation, and Vanadium calcination processes. The light absorption of the resulting M-BVO photoanode increased to approximately 92 % within the 300–500 nm wavelength range, with the absorption efficiency (ηabs) surging to 82.9 %. This represents a 23.5 % enhancement compared to its flat BiVO4 counterparts. Impressively, the photocurrent density of M-BVO reached 2.98 mA cm−2 at 1.23 VRHE, 37.6 % higher than that of flat BiVO4. These results indicate that the PEC efficiency can be significantly increased through moth-eye structuring, emphasizing the indispensable role of nanostructure research in the manufacture of high-efficiency photoanodes.
A densely packed moth-eye-structured BiVO4 photoanode was realized through simple processes of e-beam evaporation and direct printing. These enhanced optical properties improve PEC efficiency by increasing the light absorption efficiency. Display omitted
•Densely packed moth-eye-structured BiVO4 photoanode, fabricated via direct printing and e-beam evaporation, achieved a photocurrent density of 2.98 mA cm-2 and 82.9% absorption efficiency, significantly outperforming flat photoanodes.
Slippery liquid-infused porous surfaces (SLIPSs) have been actively studied to improve the limitations of superhydrophobic (SHP) surfaces, especially the defects of the nonwetting chemical coating ...layer and the weak mechanical robustness of surface micro/nanostructures. However, the SLIPSs also have several drawbacks including volatilization and leakage of lubricant caused by long-term usage. In this study, we suggest the use of icephobic, highly transparent, and self-healing solid slippery surface to overcome the limitations of both surfaces (SLIPS and SHP) by combining specific biomimetic morphology and intrinsic properties of paraffin wax. A moth-eye mimicking nanopillar structure was prepared instead of a porous structure and was coated with solid paraffin wax for water repellence. Moth-eye structures enable high surface transparency based on antireflective effect, and the paraffin layer can recover from damage due to sunlight exposure. Furthermore, the paraffin coating on the nanopillars provides an air trap, resulting in a low heat transfer rate, increasing freezing time and reducing adhesion strength between the ice droplet and the surface. The heat transfer model was also calculated to elucidate the effects of the nanopillar height and paraffin layer thickness. The antireflection and freezing time of the surfaces are enhanced with increase in nanopillar height. The paraffin layer slightly deteriorates the transmittance but enhances the icephobicity. The solar cell efficiency using a biomimetic solid slippery surface is higher than that of bare glass due to the antireflective effect. This integrated biomimetic solid slippery surface is multifunctional due to its self-cleaning, anti-icing, antireflection, and self-healing properties and may replace SLIPS and SHP surfaces.
The antireflection and absorption properties of non-metallic moth-eye structures have been intensively studied, however the research on those of metallic moth-eye structures, especially their ...absorption mechanisms, is far from enough. In this paper, the absorption properties and mechanisms of a metallic Au moth-eye structure are studied in detail. The results show that broadband perfect absorption covering the entire visible to the near infrared range with polarization independence and in a wide incident angle range can be easily realized using a single-layer single-material Au moth-eye structure. As for the absorption mechanism, in the short wavelength range of 300 nm–550 nm, due to the high loss of the Au material, the antireflection effect plays a main role. While in the long wavelength range of 550 nm–1000 nm, the widely accepted absorption mechanisms (the antireflection effect as well as the cascaded multiple plasmonic resonances, and even the combination of them) cannot completely account for the broadband perfect absorption. We found that the adiabatic nanofocusing effect of the plasmonic resonances enabled by the ultra-sharp air grooves plays a key role in the absorption. It is the nanofocusing effect that effectively increases the absorption to nearly 100% in a broad wavelength band. These findings provide a deeper insight into the absorption mechanisms of metallic moth-eye structures and offer an effective guide to explore demanded excellent absorption performance.
•This paper reported a very effective implementation method of broadband perfect absorber with excellent absorption performances. Specifically, even using a single-layer single-material Au moth-eye structure, polarization independent, wide angle, broadband perfect absorption in the entire visible range to the near infrared range can be easily obtained.•This paper provided a deeper insight into the absorption mechanisms of the metallic moth-eye structure. Specifically, though the antireflection effect plays an important role on the absorption, it is not the only reason for the broadband perfect absorption. What is more, unlike the views in many papers, only the multiple plasmonic resonances cannot lead to the broadband perfect absorption. It is found that it is the nanofocusing effect that greatly enhances the absorption of the plasmonic resonance and realizes the broadband perfect absorption.
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•Preparation of p-n heterostructure ZnO/Si moth-eye structures by multistep method.•Determined the optimum growth process to form ZnO/Si heterojunction.•The composite structures have ...antireflection performance and the super-hydrophilicity.•The composite structures have high efficiency photocatalytic properties.
The pyramidal silicon substrate is formed by wet etching, then ZnO nanorods are grown on the surface of the pyramidal microstructure by a hydrothermal method to form a moth-eye composite heterostructure. The composite heterostructure of this material determines its excellent anti-reflection properties and ability to absorb light from all angles. In addition, due to the effective heterojunction binding area, the composite micro/nano structure has excellent photoelectric conversion performance. Its surface structure and the large specific surface area gives the material super hydrophilicity, excellent gas sensing characteristic, and photocatalytic properties. Based on the above characteristics, the micro/nano heterostructure can be used in solar cells, sensors, light-emitting devices, and photocatalytic fields.
Anti‐reflection (AR) characteristics on the display surface and light outcoupling efficiency are significant factors for controlling external and internal light in organic light‐emitting diodes ...(OLEDs), respectively. This paper presents the fabrication of moth‐eye nanostructured parylene‐C films that simultaneously achieve optimized AR characteristics and enhanced OLED performance. AR performance is optimized by varying the nanostructure dimensions, resulting in a nanostructured film with a reflectance of <1%. Furthermore, applying this nanostructured film to OLEDs improved the light outcoupling efficiency by 40% compared with the reference device. Therefore, employing nanostructured parylene‐C films to enhance the optical characteristics of OLEDs is proposed.
The moth‐eye nanostructured parylene‐C films simultaneously achieve optimized anti‐reflection characteristics and enhanced OLED performance. Anti‐reflection performance is optimized by varying the nanostructure dimensions, resulting in a reflectance of <1%. Furthermore, applying this nanostructured film to OLEDs improves the light outcoupling efficiency by 40%.
Light intensity, wavelength, and photoperiod have a combined effect on chicken incubation. This study was conducted to evaluate the effect of 12-h light, 12-h dark (12L:12D) photoperiod of white ...light (380–780 nm, WL), blue light (455/447.5–462.5 nm, BL), and green light (525/515–535 nm, GL) in chicken perceived light intensity during layer incubation on hatching performance, embryo development, eye structure, and melatonin concentration. Three batches of eggs from Jinghong No. 1 layer breeder were used in this experiment. Light stimulation had no effect on hatchability, and no consistent effect on embryo weight and newly hatched chick weight. However, the average hatching time of white light group and green light group was 7.3 h and 5.5 h later than that of the control group. Therefore, the holding period of chicks was significantly shortened (P = 0.001) in these 2 light groups. Light stimulation had a significant effect on the thickness of retinal layers (P < 0.05), retinal layers of white light group was thicker than that of the other 3 groups. Melatonin levels of chicks hatched in the green light and blue light were significantly higher than that of chicks hatched in the white light and darkness (P < 0.05). It indicated that the monochrome green and blue light promoted the expression of melatonin in chicken embryos. No significant diurnal rhythms were found at the level of plasma melatonin in 4 groups on d 21 using cosine analysis. It was concluded that green light has a positive effect on embryo development and melatonin secretion, while white light probably has positive effect on eye development. Furthermore, both green and white light stimulation resulted in late hatch for layer egg incubation. The obtained results are important in determining the light protocol for chicken incubation.
Some organisms can control wettability for survival. Thus, these organisms are potential research targets for engineering applications. For example, a beetle is a desert dweller that captures water ...from fog and dew to drink. This characteristic shows potential for addressing the global water shortage. Beetle exoskeletons are composed of micropatterns with varying wettability (hydrophilic or hydrophobic). In this study, we propose a hybrid process that combines photolithography with UV nanoimprint lithography (UV-NIL). Photolithography is used to fabricate a resist micropattern on a nanopatterned substrate. In UV-NIL, the resist and UV-curable resin are released to fabricate micropatterns with different transferabilities and wettabilities. To realize this process, a resin compatible with photolithography and UV-NIL was developed.
This work reports a facile fabrication method for constructing multifunctional moth-eye TiO2/polydimethylsiloxane (PDMS) pads using soft nano-imprinting lithography and a gas-phase-deposited thin ...sacrificial layer. Mesoporous TiO2 nanoparticles act as an effective UV filter, completely blocking high-energy UVB light and partially blocking UVA light and forming a robust TiO2/PDMS composite pad by allowing the PDMS solution to easily fill the porous TiO2 network. The paraboloid-shaped moth-eye nanostructures provided high transparency in the visible spectrum and also have self-cleaning effects because of nanoroughness on the surface. Furthermore, we successfully achieved a desired multiscale-patterned surface by partially curing select regions using TiO2/PDMS pads with partial UVA ray blockers. The ability to fabricate multifunctional polymeric pads is advantageous for satisfying increasing demands for flexible and wearable electronics, displays, and solar cells.
