PEDOT:PSS/Grafted-PDMS Electrode for Fully Organic and Intrinsically Stretchable Skin-like Electronics.

Skin-like electronics ask for materials that are conducting, soft, intrinsically stretchable and highly robust. However, electronic devices often consist of multilayers, and the failure of the electronic devices mostly starts from the debonding of the layers due to poor interfacial adhesion and large mechanical mismatch. Herein, we introduce a fully organic and intrinsically stretchable electrode that achieves high robustness by grafting the substrate to improve the interfacial adhesion, and by introducing deep folds and wrinkles to improve the stretchability. The electrode exhibits a sheet resistance of 90 Ω/□ and negligible change in resistance at strains up to 100%, and shows no fatigue over 10,000 cyclic stretches to 100% strain. An iontronic skin with the electrodes is capable of detecting tiny objects exemplified by walking ants or fruit flies weighting less than 1 mg, and the device can be cyclically stretched to 30% for 1000 times without fatigue. The high robustness and stretchability of the fully organic iontronic skin lie in the wrinkle structures, small mechanical mismatch, and high interfacial strength among different layers. This work offers a general way to fabricate highly stretchable and robust devices.