Cost-effective fabrication of liquid metals via a laser induced graphene stamp for highly-stretchable integrated optoelectronics

Stretchable electronics have found widespread applications in various fields such as wearable electronics, soft robots, and bioelectronics. As an important promising alternative of traditional rigid conductors, liquid metals have demonstrated immense potential to provide high conductivity and stretchability for the stretchable electronic systems. However, limited by their fluidity and high surface tension, challenges remain in achieving liquid metal patterns with low-cost, high-precision, large-scale, and complex geometry. Here, a fabrication technique was proposed based on laser-induced graphene (LIG) stamps to enable liquid metal self-selectively adhere to substrates. Liquid metal patterns could thus be achieved in different designed geometries and could be transferred onto stretchable substrates. The liquid metal patterns exhibit exceptional electrical conductivity (3.24 × 10⁶ S/m even under 1000% strain), high stretchability (1000% strain, maximum of 2500%), small resistance changes under significant deformations (with a quality factor of 62.5 under 1000% strain), and high resolution (down to 50 μm). Utilizing the patterned liquid metals, a stretchable integrated multifunctional optoelectronic system was demonstrated, encompassing a stretchable display matrix, a pressure sensor array, a wireless powering coil, and cardiovascular sensors, which further highlight the remarkable application potential of liquid metals in optoelectronic user-interaction and advanced physiological monitoring.