High-performance BCTZ nanowires-based energy harvesting device and self-powered bio-compatible flexion sensor

Highlights: • Well-aligned BCTZ NWs were prepared by using parallel-electrode. • An ITO-coated PET sheet with ten 300 μm-wide parallel gaps was selected as the flexible substrate and electrode. • The output V_oc, I_sc and power of A-NWs-based EHD reached 9 V, 85 nA and 2 μW, respectively. It can easily light up a LED. • A self-powered bio-compatible flexion sensor was developed to apperceive the movement of knuckles. With excellent piezoelectric properties, (Ba_0.85Ca_0.15)(Ti_0.9Zr_0.1)O₃ (BCTZ) has been widely used in actuators, capacitors, sensors, etc. In this work, we fabricated BCTZ nanowires (NWs) by using sol-gel based electrospinning technique. By applying plate-electrode and parallel-electrode collectors, random BCTZ NWs (R-NWs) and well-aligned BCTZ NWs (A-NWs) were obtained. X-ray diffraction and high resolution transmission electron microscopy indicated that the NWs have good crystallinity. Furthermore, two flexible energy harvesting devices (EHDs) based on A-NWs and R-NWs were fabricated and their piezoelectric properties were measured. Under a load resistance of 1 MΩ, the output power of the R-NWs-based EHD is only ~0.95 μW while that for A-NWs-based EHD can reach up to ~2 μW, which can easily light a commercial light-emitting diode. Finally, we further demonstrated that the EHD could function as a non-invasive self-powered bio-compatible flexion sensor to apperceive the human knuckle flexion/extension movements.