A sensing-storage monolithically integrated system based on P3HT OTFT for wearable physiological sensing

Wearable health monitoring systems require seamless integration of sensing and memory functionalities for real-time physiological signal acquisition and processing. However, conventional approaches relying on hybrid integration of rigid silicon-based memory with flexible sensors suffer from mechanical mismatch and complex interfacing, limiting their practicality in continuous physiological monitoring. Here, we present a sensing-storage monolithically integrated system fabricated through low-cost solution spin-coating, which combines a flexible floating-gate organic thin-film transistor (FG-OTFT) memory with an OTFT pressure sensor. The pressure sensor exhibits a wide operating range of 0–40 kPa, a fast response time of 34 ms, and stable performance after 5000 bending cycles and over temperatures from −20 to 60 °C. When conformally attached to the finger joint, wrist, and human throat, the device delivers distinct current variations that faithfully track joint bending angles and intermittent coughing. The integrated floating-gate memory exhibits a large memory window of 18 V under ±80 V program/erase biases, a retention time exceeding 10⁵ s, and robust operation after 3000 bending cycles. A 1 × 9 memory array is used to store 7-bit ASCII-encoded characters with two additional check bits, and the stored information is wirelessly transmitted via Bluetooth low energy to a mobile application. Comparative analysis shows that the integrated system offers a shorter response time and longer data retention than previously reported OTFT-based pressure sensors and organic memories used for physiological monitoring. These results highlight a low-cost, fully flexible, and application-oriented platform for wearable electronic skins capable of simultaneous physiological sensing, data storage, and intuitive visual readout.