Pneumatic Enabled Vertical Interconnect Access of Liquid Alloy Circuits toward Highly Integrated Stretchable Electronics

Abstract Multilayer circuits, particularly in stretchable electronics, are always considered as an effective way to integrate diverse components and modules for advanced/powerful functions required in the potential applications or complex scenarios. As a desirable soft conductor, liquid alloy circuits exhibit super compliance and stretchability. However, the lacking of reliable ways to fabricate multilayer circuits like other stretchable electronics, the advantage of liquid alloy stretchable electronics is far away well exploited, especially from the perspectives of application developments. Here, based on the unique features of rapid oxidation and fluidity from liquid alloy, a facile method is presented to achieve multilayer circuits connection with vertical interconnect accesses enabled by pneumatic blowing and surface topography tuning. This approach provides a new way to achieve high integration of liquid alloy based stretchable electronics, for example, a double‐layer soft LED array, a conformal six‐layer wireless charging, and a wireless communicated wearable device for temperature and humidity real‐time monitoring. Furthermore, compatible with conventional industry process, it may open a new window for making advanced or powerful liquid alloy stretchable electronics for various applications in complex scenarios.