Transfer-Printed Wrinkled PVDF-Based Tactile Sensor-Nanogenerator Bundle for Hybrid Piezoelectric-Triboelectric...

Triboelectric sensors are known for their ultrahigh sensitivity and wide-range detectability of tactile force/pressure, all while being self-powered. However, the energy harvesting efficiency of triboelectric nanogenerators (TENGs) is often limited by relatively low output power density, when compared to other state-of-the-art microgenerators. To address this challenge and achieve high force/pressure detection while maintaining excellent tactile resolution, a hybrid nanogenerator is proposed that comprises of both triboelectric and piezoelectric components within a ferroelectric polyvinylidene fluoride (PVDF) polymer matrix. To enhance tactile sensitivity, a coupled transfer printed-spin coating technique is introduced to imprint wrinkled silicone structuring with tunable periodicity and amplitude directly onto PVDF. The hybrid output voltage of the wrinkled PVDF-based TENG utilizing the ferroelectric β phase of PVDF (FE-TENG_5) shows an impressive ≈200% increase compared to pristine FE-TENG. The highest power density (0.9 mW cm^-2) corresponds to FE-TENG with the periodicity of 5 µm. Remarkably, the imprinted FE-TENGs can detect even the slightest tactile force (<2 N), while the hybrid mechanism ensures a broad force sensing range, extending up to 100 N before saturation. This exceptional performance establishes the imprinted PVDF-based FE-TENG as a versatile tactile sensing platform for a range of cutting-edge applications, particularly in electronic skin and next-generation microelectronics.