3D Crinkled Alk-Ti₃C₂ MXene Based Flexible Piezoresistive Sensors with Ultra-High Sensitivity and Ultra-Wide Pressure Range

The conflict between high sensitivity and wide sensing range greatly limits the extensive application of flexible pressure sensors. To produce a sensor with both high sensitivity and wide range is still a challenging work. Herein, flexible and highly sensitive piezoresistive sensors with wide sensing range are developed by combining the alkali-treated 3D crinkled MXene with microstructured polydimethylsiloxane (PDMS). Sensors with different-roughness PDMS films as flexible substrate and the unprocessed MXene as the conductive material are prepared to clarify the geometric design for the ultra-wide pressure range (0–800 kPa). Then, other sensors assembled by NaOH-alkalized 3D crinkled MXenes and rough PDMS are fabricated to illustrate that the material optimization can further enhance the sensitivity (up to 1104.38 kPa⁻¹). The sensor shows a low limit of detection (17 Pa), fast response time (100 ms), good cycle stability (3000 cycles, 300 kPa), and can detect over a wide pressure range from that of the tiny pills, pulse, heartbeat, throat vibration, and the change of water weight, exhibiting a broad prospect in health monitoring systems and human-machine interaction.