Highly-robust, solution-processed flexible transparent electrodes with a junction-free electrospun nanofiber network

Flexible transparent electrodes (FTEs) are widely used in a variety of applications, including flexible displays and wearable devices. Important factors in FTE design include active control of electrical sheet resistance, optical transparency and mechanical flexibility. Because these factors are inversely proportional to one another, it is essential to develop a technique that maintains flexibility while actively controlling the sheet resistance and transparency for a variety of applications. This research presents a new method for fabricating transparent electrodes on flexible polyimide films using electrospinning and copper electroless deposition methods. A flat metal network-based electrode without contact resistance was fabricated by heat treatment and electroless deposition onto the electrospun seed layer. The fabricated FTEs exhibited a transparency exceeding 80% over the entire visible light range and a sheet resistance of less than 10.0 Ω sq^-1. Due to the heat treatment process, the adhesion between the metal network and the substrate was superior to other electrospinning-based transparent electrodes. Applicable to the large-area manufacturing process, the standard deviation of the network density of the fabricated large-area FTE was about 1%. This study does not require the polymer casting technique and has further advantages for mass production of electrodes and application to various fields.