Integrated nanodevices with the capability of storing energy are widely applicable and have thus been studied extensively. To meet the demand for flexible integrated devices, all-solid-state asymmetric supercapacitors that simultaneously realize energy storage and optoelectronic detection were fabricated by growing Co3 O4 nanowires on nickel fibers, thus giving the positive electrode, and employing graphene as both the negative electrode and light-sensitive material. The as-assembled integrated systems were characterized by an improved energy storage, enhanced power density (at least by 1860 % enhanced) by improving the potential window from 0-0.6 V to 0-1.5 V, excellent photoresponse to white light, and superior flexibility of both the fiber-based asymmetric supercapacitor and the photodetector. Such flexible integrated devices might be used in smart and self-powered sensory, wearable, and portable electronics.

Portable electronic devices which are ultrathin, lightweight and even able to roll-up have attracted much attention. Herein, we report the design of flexible all-solid-state symmetric supercapacitors by using two NiCo 2 O 4 nanowire arrays supported on Ni foams as the electrodes. The as-fabricated symmetric supercapacitors have excellent electrochemical performance with a high cell areal capacitance of 161 mF cm À2 at 1 mA cm À2 . Good electrochemical performance stability over 3000 cycles was obtained even when the device was under harsh mechanical conditions including both twisted and bent states. Asfabricated all-solid-state supercapacitors could be charged and power a commercial light-emittingdiode, demonstrating their feasibility as an efficient energy storage component and self-powered micro/nano-system. In addition, we were able to grow NiCo 2 O 4 nanowire arrays on many kinds of flexible substrates, including nickel foam, carbon cloth, Ti foil and polytetrafluoroethylene tape. Our work here opens up opportunities for the device configuration for energy-storage devices in the future wearable electronic area and many other flexible, lightweight and high performance functional nanoscale devices.

Highly flexible stacked and in-plane all-solid-state supercapacitors are fabricated on 3D hierarchical GeSe2 nanostructures with high performance, and, when configured as a self-powered photodetector nanosystem, can be used to power CdSe nanowire photodetectors.