Laser-Patternable and Stretchable Metal Electrodes Using Metal-Amine Coordination Complexes

Abstract

Coordination bonding is a crucial interaction between heteromaterials that enhances both mechanical toughness and stretchability, with mussels serving as a natural example of thriving in harsh marine environments due to this interaction. However, stretchable electronic materials based on this fundamental interaction have been rarely reported. In this study, a stretchable electrode, called the metal-amine coordination-complex-based electrode (MACE) is introduced, which involves the formation of coordination complexes between a solid metal and an organic layer. MACEs are based on a single Au layer with a thickness of a few tens of nanometers, yet they exhibit excellent stretchability of up to 70% and high durability under strain at 40% for 10 000 cycles without conventional treatments, such as pre-stretching the substrate. Additionally, the direct laser patterning process on the metal film allows for high versatility in forming desirable patterns and adjusting stretchability. Furthermore, by utilizing the mechanical and electrical properties of MACE, a reversible soft actuator with a simple laminated structure is demonstrated. This approach, based on the formation of coordination complexes between heteromaterials, provides insights into fully mechanically stretchable electronics that achieve both softness and toughness simultaneously.