Bidirectional Spiral-Inspired Kirigami Mechanical Metamaterial for Stretchable Electronics

The rapid advancement of flexible electronics and wearable sensors has heightened demands for stretchable structures that excel in conformability, dynamic motion adaptability, stability under cyclic stretches, and antidistortion properties, holding significant commercial value. Traditional stretchable designs have often compromised the fill factor to achieve in-plane stretchability by incorporating electrodes with stretchable or prestrained architectures. In this article, we introduce a novel bidirectional spiral-hinge kirigami mechanical metamaterial (BSHK-MM) design with a remarkable fill factor of 77.3%. This design significantly enhances stretchability in both in-plane (80%) and out-of-plane (12496%) directions, providing exceptional conformability, dynamic motion adaptability, and resistance to distortion. The stress-strain curve of the BSHK-MM structure was analyzed through mechanical simulation, proving the potential for further manipulation. To demonstrate the potential of this design, we fabricated a 5 × 5 inorganic light-emitting diode (LED) display based on this concept. This device functions effectively under 80% in-plane stretching and can endure 10000 cyclic stretches while returning to its original state with negligible resistance variation. Furthermore, it demonstrates exceptional resistance to distortion under both in-plane and substantial out-of-plane stretching. This LED display exemplifies the broad applicability of our BSHK-MM design concept to various types of stretchable electronics, highlighting its vast potential across a wide range of applications.