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

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