Intrinsically flexible inorganic piezoelectric subnanowire enables wireless wearable bioelectronics for non-invasive multimodal human-machine interfacing

Piezoelectric electronic skin (PE-skin) offers a significant advantage in detecting minute forces, making it highly promising for human-computer interaction in health management and medical rehabilitation. However, PE-skin often faces challenges in real-time, wireless transmission of sensing data, which can compromise both data accuracy and user comfort. Here, we report the synthesis of an inorganic piezoelectric polyoxometalate-based subnanowire, ZnBiPMo12, which possesses intrinsic flexibility and chirality, a piezoelectric coefficient of 24.9 pC/N, and notable ferroelectricity. Leveraging its piezoelectric response, ZnBiPMo12-based PE-skin (1) demonstrates high elasticity and sensitivity to tiny pressures in the range of 0.045-0.319 N. Building on this, a wireless, wearable bioelectronic (WBE) device (1A) is fabricated through multi-level assembly, enabling non-invasive, multimodal monitoring of human physiological signals, including subtle muscle contractions, blinking, breathing, and all-day heart rate. By integrating a machine learning system, a 1-based facial-computer interface (1B) can accurately recognize nine emotional expressions and twelve spoken words. This work not only introduces a typical inorganic piezoelectric material with intrinsic flexibility but also demonstrates scalable manufacturing from subnanomaterials to wireless WBEs, paving the way for non-invasive, multimodal monitoring of human physiological signals and advanced human-computer interaction. Piezoelectric materials enable bioelectronic sensing by converting mechanical stimuli into electrical signals. Xu et al. introduce intrinsically flexible polyoxometalate-based subnanowires and demonstrate their scalable integration into wireless wearable systems for human physiological monitoring.