Conductive nanofibre networks for unbreakable and transparent electrodes

Optoelectronics devices, such as touch screen panels, liquid crystal displays and solar cells, require transparent conductors. 

The transparent conductors currently used for such applications are made of indium tin oxide (ITO). However, ITO-based transparent electrodes are brittle, prone to breakage and expensive. Therefore, there is a strong demand for alternatives to ITO transparent electrodes. To address the issue, Hidetoshi Matsumoto, Masatoshi Tokita, Koichi Sakajiri and graduate student Keisuke Azuma from Tokyo Institute of Technology have developed a facile method for the fabrication of flexible and unbreakable transparent electrodes using nanofibres.

Two-dimensional aluminium (Al) nanofibre networks offering transparent conductors were fabricated by simple wet chemical etching of Al metalised polymer films using an electrospun polystyrene nanofibre mask template. The resulting Al nanowire networks - with a width of 500 nm and an area fraction of 22% - exhibited 80% optical transmittance and sheet resistance of 45 Ω ^sq-1, figures of merit that are comparable to conventional transparent conductors. Notably, the fabrication method developed by the Tokyo Tech group is scalable for mass production and cost effective.

The flexible, unbreakable and transparent electrodes are promising for applications in both large-scale and mobile optoelectronic devices including ones that are flexible. Examples of applications are large displays, large interactive touch screens, photovoltaic solar panels, LED panels, smartphones and tablets.