ITO nanowire networks as transparent and flexible electrode. (a) Sheet resistance versus optical transmission (@550 nm) for coppernanotrough19, silver nanowires (Ag NWs)17, grapheme7, ITO film and ITO nanowire networks. (b) The ITO nanowires have strong flexibility. Samples with ITO nanowires were placed in the acetone solution, shaken by sonication for 0.5 h, and then precipitated. A suspension containing ITO nanowires was obtained by removing the supernatant diluted solution. The ITO nanowire suspension was coated on silicon. (c) An electrical conductivity test under bending. (d) SEM images of the 3D ITO nanowires after being squeezed by a PET template. (e) Resistance versus bending radius for bendable transparent electrodes consisting of ITO nanowire networks or ITO films on 200-μm-thick PET substrates.