Wenbin Kang

Highly Stretchable Piezoresistive Graphene–Nanocellulose Nanopaper for Strain Sensors

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.

Stretchable and Wearable Electrochromic Devices

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.

An Intrinsically Stretchable Nanowire Photodetector with a Fully Embedded Structure

Fabrication of intrinsically stretchable nanowire photodetectors based on fully embedded structures is reported. A lithographic filtration method is used to integrate different functional layers into the photodetectors, which exhibit excellent stretchability up to 100%. The fully embedded structure enables excellent stability against repeated stretching, mechanical scratching, and adhesive forces.

Green synthesis of nanobelt-membrane hybrid structured vanadium oxide with high electrochromic contrast

Vanadium oxide with a nanobelt-membrane hybrid structure is synthesized under the structural directing effect from tannic acid, a green extract from plants. The electrochromic property of the resultant film was investigated and revealed a high contrast of 62% at the wavelength of 700 nm. Furthermore, with linear polyethylenimine (LPEI) surface treatment on ITO glass, the stability of the drop-casted film is greatly enhanced with only 18.6% reduction in transmission after 100 cycles.

Highly Transparent Conducting Nanopaper for Solid State Foldable Electrochromic Devices

It is of great challenge to develop a transparent solid state electrochromic device which is foldable at the device level. Such devices require delicate designs of every component to meet the stringent requirements for transparency, foldability, and deformation stability. Meanwhile, nanocellulose, a ubiquitous natural resource, is attracting escalating attention recently for foldable electronics due to its extreme flexibility, excellent mechanical strength, and outstanding transparency. In this article, transparent conductive nanopaper delivering the state-of-the-art electro-optical performance is achieved with a versatile nanopaper transfer method that facilitates junction fusing for high-quality electrodes. The highly compliant nanopaper electrode with excellent electrode quality, foldability, and mechanical robustness suits well for the solid state electrochromic device that maintains good performance through repeated folding, which is impossible for conventional flexible electrodes. A concept of camouflage wearables is demonstrated using gloves with embedded electrochromics. The discussed strategies here for foldable electrochromics serve as a platform technology for futuristic deformable electronics.