A transparent electrode based on a metal nanotrough network

Abstract

Transparent conducting electrodes are essential components for numerous flexible optoelectronic devices, including touch screens and interactive electronics^1,2,3,4. Thin films of indium tin oxide—the prototypical transparent electrode material—demonstrate excellent electronic performances, but film brittleness, low infrared transmittance and low abundance limit suitability for certain industrial applications^1,4,5. Alternatives to indium tin oxide have recently been reported and include conducting polymers⁶, carbon nanotubes^7,8,9 and graphene^10,11,12. However, although flexibility is greatly improved, the optoelectronic performance of these carbon-based materials is limited by low conductivity^8,13. Other examples include metal nanowire-based electrodes^{14,15,16,17,18,19,20,21,22}, which can achieve sheet resistances of less than 10Ω □⁻¹ at 90% transmission because of the high conductivity of the metals. To achieve these performances, however, metal nanowires must be defect-free, have conductivities close to their values in bulk, be as long as possible to minimize the number of wire-to-wire junctions, and exhibit small junction resistance. Here, we present a facile fabrication process that allows us to satisfy all these requirements and fabricate a new kind of transparent conducting electrode that exhibits both superior optoelectronic performances (sheet resistance of ∼2Ω □⁻¹ at 90% transmission) and remarkable mechanical flexibility under both stretching and bending stresses. The electrode is composed of a free-standing metallic nanotrough network and is produced with a process involving electrospinning and metal deposition. We demonstrate the practical suitability of our transparent conducting electrode by fabricating a flexible touch-screen device and a transparent conducting tape.