Electromechanical Reliability of Flexible Transparent Electrode of Gravure Offset Printed Invisible Silver-Grid Laminated with Conductive Polymer

Invisible Ag-grid transparent electrodes with a variety of spacing between the Ag-grid lines at a constant line width of the Ag-grid of 5 μm and a constant thickness of the Ag-grid of 0.6 μm have been prepared on a flexible polyethylene naphthalate (PEN) film substrate by a conventional gravure offset printing using our newly developed Ag nanoparticle ink. Furthermore, the Ag-grid electrodes have been laminated with a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) layer. In the Ag-grid laminated with PEDOT:PSS electrodes, the transmittance is up to 96% in the visible light region and the sheet resistance is down to 4 Ω/□. The bending flexibility and repeated bending durability of the transparent electrodes have been investigated via bending tests. The Ag-grid laminated with PEDOT:PSS electrode shows no noticeable resistance change until the electrode is bended to an outer bending radius of 1.3 mm. Moreover, the Ag-grid laminated with PEDOT:PSS electrode shows no noticeable resistance change throughout the 10,000 outer bending cycles at a bending radius of 1.5mm. The results show that the laminating with PEDOT:PSS enhances the bending reliability of the transparent electrodes.