Highly Sensitive P(VDF-TrFE)/BTO Nanofiber-Based Pressure\nSensor with Dense Stress Concentration Microstructures

Abstract

Flexible pressure sensors demonstrate\npromising potential in human–machine\ninterfaces, wearable devices, and implantable electronics. In this\nstudy, a highly sensitive pressure sensor was developed, comprising\na polyimide substrate with a high-density micropyramid array (HD-μPA),\nan active piezoelectric component of poly­(vinylidenefluoride-<i>co</i>-trifluoroethylene) [P­(VDF-TrFE)]/barium titanate (BTO)\nnanofiber mat, and silver nanowires (AgNWs) as the top electrode.\nA mold for imprinting of polyimide HD-μPA was fabricated by\nan ultraprecision microgroove fly cutting process, which can obtain\nμPA with a higher density than the mold fabricated by anisotropic\nwet etching of silicon. The piezoelectric output of the HD-μPA-based\npressure sensor was approximately 1.7 times higher than that of the\nsensor with a flat substrate. The improved sensitivity of the sensor\nwas attributed to the stress concentration effect of HD-μPA\nand elastic modulus mismatch between the polyimide HD-μPA and\nthe P­(VDF-TrFE)/BTO nanofiber mat. A pressure detection limit as low\nas 0.6 Pa was achieved for the HD-μPA-based pressure sensor,\nshowing many potential applications in flexible electronics.