Flexible neuromorphic electronics: from synaptic devices toward <?A3B2 pi6?>sensing-memory-computing circuits

In recent years, neuromorphic electronic systems, inspired by the brain’s distinctive information processing mechanisms, have attracted wide attention as a cutting-edge research field by using devices to emulate biological synapses and neurons. However, to integrate seamlessly with biological tissue, particularly human skin, such computing hardware must evolve from conventional rigid designs into flexible, deformable systems that can attach conformally. In this context, flexible neuromorphic electronics has arisen from the convergence of neuromorphic computing and flexible electronics. By emulating synaptic and neuronal functions on flexible substrates, these systems enable brain-inspired information processing with high efficiency and ultralow power consumption, making them attractive for smart wearables, digital health, and brain-computer interface. However, despite rapid advances in flexible synaptic devices and their system-level practical applications, a cross-disciplinary synthesis that connects the materials and device physics to circuit integration and application is still missing. Here, we provide a systematic review following a device-to-system application framework. It first summarizes recent advances in flexible artificial synapses, highlighting their bio-inspired emulation of neural functions. Then, the discussion shifts to neuromorphic circuits and systems constructed from such devices, focusing on collaborative sensing-computing and heterogeneous integration strategies that are advancing toward genuinely integrated sensing-memory-computing systems. We also highlight the emerging applications toward next-generation bio-intelligent systems, including wearables, health monitoring, and human-machine interaction. Finally, the key challenges and future directions are summarized, aiming to provide a valuable reference for developing the next-generation of efficient, intelligent, and biocompatible intelligent bionic hardware.