Sonochemically synthesized Al-doped ZnO nanorods-based flexible piezoelectric nanogenerators for durable energy harvesting

This study presents a high-performance piezoelectric nanogenerator (PENG) based on aluminum-doped zinc oxide (Al:ZnO) nanorods synthesized via a novel sonochemical method. This rapid, cost-effective, and reproducible approach enables the synthesis of ZnO nanorods (ZnO NRs) under ambient conditions. The PENG, fabricated on a 177 µm flexible Indium Tin Oxide (ITO) coated polyethylene terephthalate (PET) substrate, benefits from optimized aluminum doping, enhancing the output voltage. Structural analyses conducted using atomic force microscopy (AFM), scanning electron microscopy (SEM), and X-ray diffraction (XRD) demonstrated that the synthesized ZnO nanorods possessed a high degree of crystallinity. The synthesis process was carefully fine-tuned to avoid thermal damage, keeping the substrates intact and fully functional. Electrical performance evaluations revealed a maximum peak-to-peak open-circuit voltage of around 6 V with a mean of 3.96 V and a standard deviation(S) of 1.27 V generated under mechanical stimulation, achieved through a finger-tapping method at a frequency of 2 Hz.