Thin Ag Layer Inserted GZO Multilayer Grown by Roll-to-Roll Sputtering for Flexible and Transparent Conducting Electrodes

We prepared a nanoscale Ag-layer-inserted Ga-doped ZnO (GZO) multilayer on a flexible poly(ether sulfone) (PES) substrate using a continuous roll-to-roll (RTR) sputtering system at room temperature for the fabrication of highly flexible and transparent conducting oxide electrodes. When the thickness of the Ag interlayer was optimized (12 nm), the resulting GZO/Ag/GZO (GAG) multilayer showed a resistivity of and a transparency of 87.2% without in situ or ex situ annealing processes. However, although it exhibited lower resistivity, the GAG multilayer showed decreased optical transparency above the critical Ag interlayer thickness of 12 nm due to severe light scattering caused by the Ag layer. The results of bending tests demonstrated that the GAG multilayer resistance varies depending on the bending radius of the sample during repeated bending cycles. The constant surface morphology and resistance of the GAG multilayer even after the performance of bending tests indicate that RTR sputter grown GAG multilayers are promising as flexible transparent conducting electrodes for use in cost-efficient flexible displays and photovoltaics.