Rollerball‐Pen‐Drawing Technology for Extremely Foldable Paper‐Based Electronics

It is reported that graphene oxide (GO) can work as the dispersing, associate thickening, stabilizing, adhesive, oxidation‐resistant, and mechanical reinforcing agents simultaneously to formulate a drawable conductive ink with silver nanowire (AgNW). The synergistic effect of combining AgNW with GO can bring forth the AgNW‐GO dynamic network, which imparts appropriate viscosity and rheological property to the ink for reliable rollerball‐pen drawing on paper and plastic substrates and enables the drawn conductive traces to simultaneously possess high conductivity, remarkable foldability, and stability. The electrical conductivity of the rollerball‐pen drawn electrodes with mild post‐treatment condition by drying at 25 °C for ≈5 min after writing on paper can achieve 2.3 × 104 S cm−1. The drawn electrodes are used as extremely foldable electrodes that can retain a record high conductivity of 1.4 × 104 S cm−1 after 1000 folding–unfolding cycles. The feasibility of the drawable conductive ink is further demonstrated by fabricating paper‐based conductive circuits and a capacitive touch screen sensor with outstanding foldability.