3D-Printed PVDF-Based Hybrid Nanogenerators With Dominant Triboelectric Output for High-Sensitivity Force Sensing

Fused filament fabrication (FFF)-based 3D-printing technology for thermoplastics is known to be a versatile process that enables wide-ranging structural improvements (rheological, mechanical and electrical properties) of polymer-based materials for energy harvesting applications. In this study, we report a 3D-printed poly(vinylidene difluoride, PVDF)-based nanogenerator (3D-HTPENG) that operates in a hybrid synergistic mechanism incorporating predominantly triboelectric effect (electrostatic induction and friction-based charge generation) with minor piezo-electric contribution. Under vertical contact-separation operation, the device delivers a peak open-circuit voltage of ~260 V and a short-circuit current of ~16 μA, corresponding to a maximum power density of ~690 μW/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>. Surface charging and electrostatic induction under mechanical loading serve as the primary source of voltage generation, while the piezoelectric components (²- and ϒ-phases) contributes secondary outputs, particularly during low-force deformations. AFM and FTIR analysis confirmed the presence of polar ²- and ϒ-phases in the printed films, with crystallization behavior influenced by film thicknesses (0.1-0.4 mm). The system demonstrates excellent short-term stability (>5000 cycles), and exhibits practical utility in tactile-integrated sensing, wearable electronics, and soft robotic segments. Our findings suggest that PVDF-based 3D-printed devices can function as high-output triboelectric nanogenerators with supplementary piezoelectric effects. Owing to stronger triboelectric output, the 3D-HPTENG is also an excellent multidirectional force sensing device alternative to conventional resistive sensors that can be utilized as tactile sensors and arrays for applications in wearable technologies, soft robotics and internet-of-things (IoTs).