Flexible PVDF-HFP Piezoelectric Nanofibers with In Situ rGO and BCZT for High-Sensitivity Tactile Sensing and Haptic-Visual Feedback

Flexible polymer-based piezoelectric sensors are promising for electronic skin and human–machine interfaces, but challenges remain in achieving efficient electromechanical conversion and sensitive low-pressure detection due to insufficient polarization and weak interfacial coupling within polymer matrices. Here, we report a porous poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) nanofibrous piezoelectric sensor integrating partially reduced graphene oxide (rGO) and lead-free (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3(BCZT), fabricated by electrospinning and thermal annealing. The synergistic effects of rGO and BCZT promote β-phase formation, interfacial polarization, and charge transfer, resulting in enhanced piezoelectric output and low-pressure sensing performance. The optimized sensor delivers an output voltage of 11.25 V, a sensitivity of 6.44 V kPa–1 below 0.5 kPa, a detection limit below 12 Pa, and a rapid response time of 16.5 ms. The device was further integrated into a tactile–visual feedback interface for non-auditory rhythm perception. Benefiting from the distinct temporal features of the piezoelectric signals, six tactile interaction modes were accurately decoded by a one-dimensional convolutional neural network (1D CNN), achieving 100% accuracy on the test. This work provides an interface-engineering strategy for high-performance flexible piezoelectric sensors and advances their use in intelligent tactile perception and multimodal human–machine interaction.