Nanoscale networked single-walled carbon-nanotube electrodes for transparent flexible nanogenerators

We have investigated a nanoscale networked single-walled carbon-nanotube (SWCNT) electrode as a top cathode electrode of transparent flexible (TF) nanogenerators, so as to improve the energy scavenging performance and the system stability. The morphological effect and the electrical stability of SWCNT films for TF nanogenerators are investigated. It is found that SWCNT films have a nanosized network surface with pores, exceeding 100 nm in size, which favor ZnO nanorods contacting the CNT electrode, increasing the current generation and reducing the series resistance of the device for the effective transportation of piezoelectrically generated electrons from the nanogenerators. The nanogenerator using the CNT electrode with transparency 84% (at wavelength 550 nm) and a sheet resistance of 220 Ω/square had approximately 5 times the current density as with an indium-tin oxide-based nanogenerator. Moreover, the low variation (<100 Ω) in the resistance of CNT films during bending tests, and small change of the resistance of the film before and after the bending test (less than 1.1% on average), can support durable, stable, and reliable CNTbased TF nanogenerators.