Flexible Self-Powered Integrated Sensing System with 3D Periodic Ordered Black Phosphorus@MXene Thin-Films.

Accurate and continuous detection of physiological signals without the need for an external power supply is a key technology for realizing wearable electronics as next-generation biomedical devices. Herein, it is shown that a MXene/black phosphorus (BP)-based self-powered smart sensor system can be designed by integrating a flexible pressure sensor with direct-laser-writing micro-supercapacitors and solar cells. Using a layer-by-layer (LbL) self-assembly process to form a periodic interleaving MXene/BP lamellar structure results in a high energy-storage capacity in a direct-laser-writing micro-supercapacitor to drive the operation of sensors and compensate the intermittency of light illumination. Meanwhile, with MXene/BP as the sensitive layer in a flexible pressure sensor, the pressure sensitivity of the device can be improved to 77.61 kPa at an optimized elastic modulus of 0.45 MPa. Furthermore, the smart sensor system with fast response time (10.9 ms) shows a real-time detection capability for the state of the human heart under physiological conditions. It is believed that the proposed study based on the design and integration of MXene materials will provide a general platform for next-generation self-powered electronics.