Pre-stretched wrinkled CuO/laser-induced graphene heterostructures for ultrasensitive strain sensing and bioelectric monitoring

Concurrently achieving high sensitivity and mechanical resilience remains a central challenge in flexible electronics. This study presents a solution through a highly responsive strain sensor based on hierarchically wrinkled copper oxide/laser-induced graphene heterostructures. An integrated fabrication approach combining in situ precursor doping with a transfer pressure-tailored pre-stretching strategy establishes a directional wrinkled architecture with optimized interfacial bonding, revealing the intrinsic correlations among transfer pressure, microstructure, and sensing performance. This structure resolves the intrinsic trade-off between sensitivity and stretchability, yielding a sensor that exhibits a gauge factor of 12 375, a 60 ms response, and exceptional stability over 7000 cycles. Finite element modeling confirms that the multiscale wrinkled architecture accommodates large deformations through structural unfolding, while density functional theory calculations validate that the CuO decoration optimizes the electronic structure to facilitate rapid interfacial charge transfer. Demonstrated applications underscore its capability to precisely capture diverse biosignals, ranging from large-scale human motion to subtle physiological signals such as radial artery pulses, and to provide high-fidelity electrocardiogram monitoring with performance comparable to that of commercial Ag/AgCl electrodes. This work establishes a promising low-cost, high-performance platform for next-generation wearable healthcare.