In arthropods, evolution has created a remarkably sophisticated class of imaging systems, with a wide-angle field of view, low aberrations, high acuity to motion and an infinite depth of field. A challenge in building digital cameras with the hemispherical, compound apposition layouts of arthropod eyes is that essential design requirements cannot be met with existing planar sensor technologies or conventional optics. Here we present materials, mechanics and integration schemes that afford scalable pathways to working, arthropod-inspired cameras with nearly full hemispherical shapes (about 160 degrees). Their surfaces are densely populated by imaging elements (artificial ommatidia), which are comparable in number (180) to those of the eyes of fire ants (Solenopsis fugax) and bark beetles (Hylastes nigrinus). The devices combine elastomeric compound optical elements with deformable arrays of thin silicon photodetectors into integrated sheets that can be elastically transformed from the planar geometries in which they are fabricated to hemispherical shapes for integration into apposition cameras. Our imaging results and quantitative ray-tracing-based simulations illustrate key features of operation. These general strategies seem to be applicable to other compound eye devices, such as those inspired by moths and lacewings (refracting superposition eyes), lobster and shrimp (reflecting superposition eyes), and houseflies (neural superposition eyes).

Wavy shaped PANI/graphene electrodes enable stretchable all-solid-state supercapacitors to maintain high electrochemical capacitance and mechanical strength simutaneously.

Two-dimensional materials provide an ideal platform for studying the fundamental properties of atomic-level thickness systems, and are appropriate for lots of engineering applications in various fields. Although 2D materials are the thinnest membranes, they have been revealed to have high impermeability even to the smallest molecule. By the virtue of this high impermeability of the 2D materials in combination with their other unique properties, 2D materials open up a variety of applications that are impossible for conventional membranes. In this review, the latest applications based on high impermeability and selective permeation of these 2D material membranes are overviewed for different fields, including environmental control, chemical engineering, electronic devices, and biosensors. The working mechanism for each kind of application is described in detail. A summary and outlook is then provided on the challenges and new directions in this emerging research field.

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The filling fraction limitation (FFL) in n-type CoSb3 skutterudites is far below that of p-type (Fe,Co)­Sb3-based skutterudites, and it is critical to increase FFL for accomplishing high thermoelectric figure of merit (ZT max). Here, a series of Yb x Co4–y Fe y Sb12 alloys with x = 0.25–0.5 and y = 0.1–0.5 were synthesized, which demonstrate a clear increase of the FFL of Yb from ∼0.3 in CoSb3 to 0.5. Ultralow thermal conductivities of 2.0–2.5 W/m·K at 300 K and 1.75 W/m·K at ∼600 K have been achieved, which are the lowest values reported among skutterudite materials and comparable with p-type skutterudites. These ultralow thermal conductivities result from the combination of secondary phase scattering and phonon scattering from dynamic electron exchange between Fe2+ and Co3+. High ZT max values of 1.28 at 740 K and 1.34 at 780 K are obtained, which are among the best values reported in the temperature range of 740–800 K. The temperature at which maximum ZT max appears is shifted below 850 K. These results are highly exciting toward the development of multistage segmented and cascade thermoelectric power generators for in-air operations.