It is a completely transparent and flexible energy conversion and storage device that you can bend and twist like a poker card.
It continues a line of prototype devices created at the USC Viterbi School of Engineering that can perform the electronic operations now usually handled by silicon chips using carbon nanotubes and metal nanowires set in indium oxide films, and can potentially do so at prices competitive with those of existing technologies.
The device is a supercapacitor, a circuit component that can temporarily store large amounts of electrical energy for release when needed. A team headed by Chongwu Zhou describes it a newly-published paper on "Flexible and Transparent Supercapacitor based on Indium Nanowire / Carbon Nanotube Heterogeneous Films" in the journal Applied Physics Letters (Vol.94, Issue 4, Page 043113, 2009).
Its creators believe the device points the way to further applications, such as flexible power supply components in "e-paper" displays and conformable products.
The device stores an energy density of 1.29 Watt-hour/kilogram with a specific capacitance of 64 Farad/gram. By contrast, conventional capacitors usually have an energy density of less than 0.1 Wh/kg and a storage capacitance of several tenth millifarads.
Zhou, who holds the Jack Munushiun Early Career Chair at the USC Ming Hsieh Department of Electrical Engineering, worked with USC graduate students Po-Chiang Chen and Sawalok Sukcharoenchoke, and post-doc Guozhen Shen.
The group incorporated metal oxide nanowires with carbon nanotubes (CNTs) to form heterogeneous films and further optimized the film thickness attaching on transparent plastic substrates to maintain the mechanical flexibility and optical transparency of the supercapacitors.