Surface Tension‐Driven Transfer Printing for Ultrathin Curved Electronics

Ultrathin curved electronics, distinct from traditional rigid and planar electronics, exhibit superior conformability and compatibility, which offer promising applications in flexible sensing and health monitoring. However, existing fabrication methods encounter limitations regarding electronics thickness and conformal integration onto curved substrates. Here, a transfer printing method driven by surface tension is presented, which can integrate submicron ultrathin electronics onto 3D curved substrates with complex surfaces, even with a significant curvature. The entire transfer printing process is damage‐free, and the resulting ultrathin electronics exhibit exceptional conformability to substrates with concave, convex, and irregular curvatures. The related surface tension‐driven transfer printing mechanism is explored through theoretical models. The maximum allowable mass, denoting the printing capability, and the printing velocity, representing the printing efficiency, are considered. To validate the capability of the surface tension‐driven transfer printing technique, a 600 nm‐thick temperature sensor is integrated onto a radiofrequency (RF) puncture needle with a radius of 0.45 mm to perform the real‐time temperature monitoring.