Design of Ag/PDMS electrodes with a pillar structure for stretchable electronics

Recent efforts in the development of soft and conformable electrodes shed light on the application of flexible electronic devices including sensors, displays, and wearable devices. The application of the electrodes requires the maintenance of the electrical and mechanical properties under various mechanical deformations. Although significant advancements have been made in the field of soft and conformable electrodes, several limitations still exist for real-life applications. One of the problems is the serious damage or destruction of joining parts between soft electrodes and rigid electronic components, which can significantly harm the reliable performance of electronic devices. Herein, we introduce a pillar structure on stretchable electrodes that enhances the stability of joining parts between soft matter and rigid components. Design-form factors of the pillar structure were investigated by experimental verification combined with the finite element method. The stretchable electrodes with the pillar structure were prepared using a simple mold and via-hole filling with blending conductive fillers. Under repetitive stretching up to 30%, the electrodes exhibited excellent durability without losing their electrical properties. As a representative work for industrial application, light-emitting diodes were positioned on top of the prepared pillar structure using pick-and-place methods. Under stretching up to 30%, no blinking or flickering was observed from the LED. Based on the results, it is suggested that the pillar structure of the stretchable electrodes, used as a joining part, can be a good solution for preventing the mechanical failure between stretchable electrodes and rigid electronic components.