Ce Yao Foo

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.

Large Areal Mass, Flexible and Free-Standing Reduced Graphene Oxide/Manganese Dioxide Paper for Asymmetric Supercapacitor Device

Well-separated RGO sheets decorated with MnO2 nanoparticles facilitate easy access of the electrolyte ions to the high surface area of the paper electrode, enabling the fabrication of a thicker electrode with heavier areal mass and higher areal capacitance (up to 897 mF cm(-2) ). The electrochemical performance of the bent asymmetric device with a total active mass of 15 mg remains similar to the one in the flat configuration, demonstrating good mechanical robustness of the device.

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.

Significant electrochemical stability of manganese dioxide/polyaniline coaxial nanowires by self-terminated double surfactant polymerization for pseudocapacitor electrode

Manganese dioxide/polyaniline coaxial nanowire networks are prepared by using double surfactant approach. This approach improves the interaction between the two active materials which has been confirmed by FTIR and XPS measurements, and yields a controllable uniform thin coating of polyaniline on the well-dispersed manganese dioxide nanowires. This hybrid heteronanostructure enhances the conductivity and capacitive performance of the supercapacitor electrode. The electrochemical test delivers specific capacitance as high as 498 and 873 F g−1 at 2 and 0.25 A g−1, respectively. Good cycling stability of up to 5000 cycles (5% capacitive degradation) outperforms other currently available redox nanocomposite electrodes. This result shows that the interaction among the active materials and improved nanostructure design are the two important factors to boost up the electrochemical performance of the hybrid nanomaterials. This work illustrates a promising platform that can be adopted for a myriad of metal oxide-conducting polymer nanocomposites while reaping the benefit as low cost electrode material for supercapacitor application.

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.