Flexible electronic skins (e‐skins) with high sensitivity and broad‐range pressure sensing are highly desired in artificial intelligence, and human–machine interaction. Capacitive‐type e‐skins have a ...simple configuration, but the change in dimensions of the dielectric layer is often quite limited, although introducing surface microstructures might improve the sensitivity in some extent. Moreover, such surface structures typically require costly microfabrication methods to fabricate. Here, a low‐cost microstructured ionic gel (MIG) with uniform cone‐like surface microstructures for high‐performance capacitive e‐skins is reported. The MIG film is templated from a Calathea zebrine leaf using soft lithography, and sandwiched by two flexible electrodes. The device exhibits a low limit of detection down to 0.1 Pa, a ultrahigh sensitivity of 54.31 kPa−1 in the low pressure regime (<0.5 kPa), and the sensitivity keeps larger than 1 kPa−1 over a broad‐range pressure from 0.1 Pa to 115 kPa. Electric double layers (EDL) form on both the top and bottom interfaces, and the area of EDL of the rough interface increases as the cones are compressed. Such ionic skins with biomimetic gel templated Calathea zebrine leaf allow for sensitive tactile sensing in the applications of human–machine interaction.
An ionic gel film with cone‐like microstructures replicated Calathea zebrine leaf is applied in electronic skin. The device exhibits a maximum sensitivity of 54.31 kPa−1, a low limit of detection <0.1 Pa, and a fast response time of 29 ms. The device is potentially useful in human–machine interaction, motion detection, and artificial intelligence.
As the lightest and most electropositive material, lithium metal is regarded as the ultimate anode material for next-generation high-energy batteries. However, uncontrolled dendritic lithium growth ...as well as low Coulombic efficiency hinders its widespread application in secondary batteries. Interfacial modification of anodes with protective layers has been proved to be an effective way to inhibit the growth of ramified lithium. Here we report on a freestanding, highly flexible nanostructured carbon film, which is ready to be transferred onto electrodes with great ease. We show that such mechanically robust carbon films can effectively suppress the growth of Li dendrites upon cycling at practical current densities (0.25–1.0mAcm−2) with significantly improved Coulombic efficiency up to ~99.5% for over hundreds of cycles and thousands of operation hours. Notably, this semi-tubular carbon film demonstrated instant, reliable protection to electrodes in not only reactive electrolytes but also ambient environment with high humidity, offering a practically feasible route toward the dendrite-free lithium metal batteries.
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•A freestanding, highly flexible nanostructured carbon film is fabricated.•Such mechanically robust carbon films can suppress the growth of Li dendrites.•The semi-tubular carbon film can also protect Li anodes in ambient environment.
The effect of cysteine on the corrosion characteristics of Cu5Zn5Al1Sn alloy in 3.5 wt% NaCl solution has been studied by electrochemical and surface characterization techniques in various immersion ...times. The results of electrochemical impedance spectroscopy (EIS) revealed that the degradation of Cu5Zn5Al1Sn alloy occurred in 3.5 wt% NaCl and was aggravated with increasing immersion time. The results of inhibition efficiency calculated from EIS data showed that cysteine can act as an effective anti-corrosion substance, which was also proved by the less eroded morphology of the alloy surface observed on scanning electron microscopy (SEM). Furthermore, the elemental analysis of alloy surfaces was investigated by Raman, electron dispersion spectroscopy
EDS), and X-ray photoelectron spectroscopy (XPS), which confirmed the presence of S and N species. An adequate adsorption isotherm and inhibition mechanism was also suggested based on EIS results.
The spin and orbital angular momentum (SAM and OAM) of light is providing a new gateway toward high capacity and robust optical communications. While the generation of light with angular momentum is ...well studied in linear optics, its further integration into nonlinear optical devices will open new avenues for increasing the capacity of optical communications through additional information channels at new frequencies. However, it has been challenging to manipulate the both SAM and OAM of nonlinear signals in harmonic generation processes with conventional nonlinear materials. Here, we report the generation of spin-controlled OAM of light in harmonic generations by using ultrathin photonic metasurfaces. The spin manipulation of OAM mode of harmonic waves is experimentally verified by using second harmonic generation (SHG) from gold meta-atom with 3-fold rotational symmetry. By introducing nonlinear phase singularity into the metasurface devices, we successfully generate and measure the topological charges of spin-controlled OAM mode of SHG through an on-chip metasurface interferometer. The nonlinear photonic metasurface proposed in this work not only opens new avenues for manipulating the OAM of nonlinear optical signals but also benefits the understanding of the nonlinear spin–orbit interaction of light in nanoscale devices.
Motivated by the rising cost of tin‐doped indium oxide (ITO), the search for new transparent electrode materials to replace ITO is ongoing. TiN exhibits high electric conductivity, however, it is ...generally non‐transparent. Here, nanostructured TiN fiber patterns are synthesized on quartz glass and the resulting materials have a combination of high electric conductivity and optical transparency. A low sheet resistance of 15.8 Ohm sq−1 at 84% transparency is achieved on TiN nanofiber arrayed quartz glass. The achievements show a successful integration of electric and optical properties in ceramic nanofibers and provide a method for finding new materials to replace traditional ITO‐based transparent electrodes.
TiN nanofibers are successfully fabricated and assembled on quartz glass via electrospinning. High conductivity and transmittance are found in the TiN nanofiber network. A sheet resistance of 15.8 Ohm sq−1 at 84% transparency can be achieved, which makes electrospun TiN nanofibers promising candidates for new transparent electrode materials.
One‐dimensional sensing materials that are prepared via electrospinning and controlled annealing exhibit intrinsic properties, such as electron transmissivity, magnetic susceptibility, specific heat ...capacity, as well as optical and mechanical characteristics. Particularly, the electronic transmission characteristics of the ceramic fiber materials, such as the electrical conductivity, photocurrent, magnetoresistance, nanocontact resistance, and dielectric properties, exhibited great potential for applications in the next generation of electronic sensing devices. First, electrospun ceramic materials with different structural and functional characteristics were reviewed here, after which the strategies for improving their properties, as well as the method for assembling the flexible devices, are summarized. Moreover, the electrospun ceramic nanofibers were detailedly discussed regarding applications in device construction and wearable electronics, such as photosensors, gas sensors, mechanical sensors, and other energy storage devices. Finally, the future development direction of the electrospinning technology for multifunctional and wearable electronics skin was proposed.
We report stretchable metal-mesh transparent electrodes (TEs) with excellent electrical conductivity (<2 Ω/sq) and optical transparency (>80%) under up to 55% strain. The figures of merit on these ...electrodes, as defined as the ratio between electrical conductivity and optical conductivity, are among the highest reported for stretchable TEs under moderate stretching. Moreover, we demonstrate their application in a stretchable electroluminescent (EL) light-emitting film as top and bottom electrodes. EL lighting devices require low-resistance electrodes to unleash their potential for large-area low-power-consumption applications, in which our highly conductive and transparent stretchable TEs provide an edge on other competitor approaches. Importantly, our stretchable metal-mesh electrodes are fabricated through a vacuum-free solution-processed approach that is scalable for cost-effective mass production. We also investigate the fracture and fatigue mechanisms of stretchable metal-mesh electrodes with various mesh patterns and observe different behaviors under one-time and cyclic stretching conditions. Our solution-processed fabrication method, failure mechanism investigation, and device demonstration for metal-mesh stretchable TEs will facilitate the adoption of this promising high-performance approach in stretchable and wearable electronics applications.
Tunable multishape memory polymers offer intriguing opportunities for memorizing multiple temporary shapes with tunable transition temperatures from one material composition. However, such multishape ...memory effects have been exclusively correlated with the thermomechanical behaviors of polymers, significantly limiting their applications in heat-sensitive scenarios. Here we report a nonthermal tunable multishape memory effect in covalently cross-linked cellulosic macromolecular networks, which spontaneously organize into supramolecular mesophases by water evaporation induced self-assembly. The supramolecular mesophase endows the network with a broad, reversible hygromechanical response combined with a unique moisture memory effect at ambient temperature, enabling diverse multishape memory behaviors (dual-, triple-, and quadruple-shape memory) under highly tunable and independent control of relative humidity (RH) alone. Significantly, such a hygroscopic tunable multishape memory effect readily extends the implications of shape memory polymers beyond the conventional thermomechanical regimes with potential advantages for biomedical applications.
Flexible transparent electrodes are an indispensable component of next‐generation soft optoelectronics such as wearable electronics and electronic artificial skins (E‐skins). Among the existing ...candidate materials, metal nanotrough networks exhibit optimal overall optoelectronic performance with impressive bendability. However, their further practical applications are hindered by their limited mechanical stretchability, which is highly desired in biointegrated systems. Here it is demonstrated that superior mechanical stretchability with tensile strains up to 300% can be achieved in Au nanotrough networks by introducing an in‐plane sinusoidal wavy structure. For the first time it is shown that with a precisely tuned nanotrough geometry along with an optimized network configuration, the buckled Au nanotrough network can be repeatedly stretched to strains up to 120% for 100 000 cycles, exhibiting excellent fatigue performance. Such highly stretchable and fatigue‐free (at a high tensile strain up to 100%) Au nanotrough networks present a competent sheet resistance (Rsh ≈ 10 Ω sq−1) with high optical transparency (T = 91%), which are demonstrated to be highly compatible with human skins as conformal flexible transparent electrodes.
A highly stretchable transparent electrode based on in‐plane buckled Au nanotrough networks is engineered, showing excellent stretchability (300% strain) with no fatigue upon cyclic stretching to 100% strain for 100 000 cycles. Combined with superior optoelectronic performance (sheet resistance ≈1 Ω sq−1 at optical transmittance of 91%), the Au nanotrough networks can be applied to human skins as flexible transparent electrodes.
The specific stacking mode of D/A blocks is often considered to largely determine the physicochemical properties of cocrystals. However, this rule may fail when encountering a large degree of ...(integer or near-integer) charge transfer situations. Herein, we explore the extensive correlations between the possible smallest structural units, stacking modes, and near-infrared photothermal conversion (NIR-PTC) properties of F4TCNQ-based cocrystals with typical features of integer-charge-transfer. Surprisingly, these cocrystals with distinct stacking modes display analogous D–A interactions, broad red-shift absorption, ultrafast (1–3 ps) relaxation dynamics of excited states, and excellent NIR-PTC properties. This supports that the resulting “D+A–” ion pairs from integer-charge-transfer may serve as the primary structural units beneath the secondary stacking modes to dominate the property of cocrystals. The stacking modes play an important but only secondary role. This work provides new insights into the structure–dynamics–property correlations and modular design of organic cocrystals for PTC and other applications.
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