Highly stretchable graphene-nanocellulose composite nanopaper is fabricated for strain-sensor applications. Three-dimensional macroporous nanopaper from crumpled graphene and nanocellulose is embedded in elastomer matrix to achieve stretchability up to 100%. The stretchable graphene nanopaper is demonstrated for efficient human-motion detection applications.

The development of mechanically "robust" EL devices that can confront different demanding mechanical deformations, such as fl exing, folding, twisting, and stretching without incurring damage, is the primary requirement for fabricating selfdeformable EL devices. Reported attempts have demonstrated polymer light-emitting materials for intrinsically stretchable EL devices. [3][4][5][6][7]12 ] Different strategies have also been employed by engineering stretchable structures with assembled rigid inorganic light-emitting elements. [ 1,2,13,14 ] The substrates and electrodes of devices can be stretched while the light-emitting elements are kept intact during stretching. Here, a different method has been developed to fabricate an intrinsically stretchable inorganic EL device with both stretchable conductors and light-emitting layers. The elastic EL device could sustain its performance at stretching strains as large as 100% (close to the mechanical failure of the host elastomer). The simplicity of the device fabrication together with its excellent stretchability enabled the integration with actuators, which could drive the elastic EL devices into dynamic shapes. Dielectric elastomer actuators (DEAs) are emerging "smart materials" that can generate mechanical motions with applied electrical fi elds. DEAs have demonstrated extraordinary mechanical actuation performance with area strain reaching beyond 200% on prestrained elastomers; [15][16][17] this exceeds most actuators based on other working mechanisms, such as piezoelectric actuators (≈5%), [ 18 ] ionic gel actuators (≈40%), [ 19 ] and natural muscle (≈100%). [ 20 ] With their intrinsic stretchability, ease of minimization, high power density, and low-cost fabrication, DEAs have been applied in many applications such as wearable tactile display devices, [ 21,22 ] highspeed electromechanical transducers, [ 23,24 ] and smart artifi cial muscles [ 20,25 ] etc. In this report, DEAs are demonstrated to be ideal shape display components to integrate with stretchable EL devices. An unprecedented self-deformable EL device is fabricated by the innovative method in this work.A schematic drawing of the stretchable EL device is represented in Figure 1 a. The stretchable EL device was fabricated with a simple all-solution processable method. In brief, AgNW networks were fi rstly spray-coated onto the polydimethylsiloxane (PDMS) substrate, forming the bottom electrode. ZnS:Cu microparticles mixed with liquid PDMS were then spun onto the bottom electrode. ACEL devices have been developed for display or lighting applications for a few decades and have attracted persistent interest for their simple device architecture and low production cost. [26][27][28] ZnS:Cu is a widely available ACEL material with well-studied and understood emission behavior. [ 29,30 ] Its emission colors can be easily tuned by using different active dopants or adjusting the dopant concentrations. After crosslinking, the ZnS:Cu/PDMS composite layer harvests the excellent stretchability from the PDMS matrix with...

Stretchable and wearable WO3 electrochromic devices on silver nanowire (AgNW) elastic conductors are reported. The stretchable devices are mechanically robust and can be stretched, twisted, folded, and crumpled without performance failure. Fast coloration (1 s) and bleaching (4 s) time and good cyclic stability (81% retention after 100 cycles) were achieved at relaxed state. Proper functioning at stretched state (50% strain) was also demonstrated. The electrochromic devices were successfully implanted onto textile substrates for potential wearable applications. As most existing electrochromic devices are based on rigid technologies, the innovative devices in their soft form hold the promise for next-generation electronics such as stretchable, wearable, and implantable display applications.

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Polyaniline (PANI), a promising conducting polymer for supercapacitor, exhibits high specific capacitance and good rate capability. However, it suffers from low cycling stability due to the breakage or scission of polymer chains and loss of contact caused by the volume change during the charge–discharge, as well as the irreversible oxidation and reduction. Here, a strategy for using aniline tetramers loaded on graphene oxide (AT‐GO) is developed to prevent chain breaking and increase the tolerance of volume change. The potential window is also controlled to reduce the irreversible reactions. In a three electrode test, AT‐GO exhibits a good cycling stability with specific capacitance remaining more than 93 to 96% after 2000 cycles. In a two electrode test, the specific capacitance remains 97.7% of its initial specific capacitance after 2000 cycles by suppressing the side reactions. AT‐GO also shows a high specific capacitance of more than 769 F g−1 at 1 A g−1 and it remains 581 F g−1 at 60 A g−1, suggesting a good rate capability. These results suggest that AT‐GO is a promising electrode material for practical applications.