Flexible piezoelectric nanogenerators (PNGs) with high power-conversion efficiency are of great interest. Here, we propose wearable PNGs based on pristine magnesium (Mg)-doped GaN (GaN:Mg) and GaN:Mg/ZnO coaxial nanowires (NWs) exhibiting state-of-the-art high-voltage and -current outputs. The PNGs were designed to suppress internal screening by a reduction in the diameter of the NWs, successful incorporation of Mg in GaN NWs as a p-type dopant, and deposition of a ZnO shell on the GaN:Mg NWs. The Fermi-level pinning reduces free carriers in thin NWs (diameter up to ~30 nm). By tuning the size of the metal–alloy catalyst, we obtained NWs with diameters ranging from 30 to 50 nm. To deplete the NWs fully of free carriers, Mg is incorporated without activation, which enhanced the resistance of GaN:Mg NWs by forming inactive Mg–H complexes. The flexible PNG fabricated with pristine GaN:Mg NWs exhibited the maximum output voltage and current of 52 V and 23 µA, respectively. The junction current screening was suppressed by depositing a ZnO shell with an optimized thickness of 10 nm on GaN:Mg NWs. The PNG fabricated with GaN:Mg/ZnO coaxial NWs showed an enhanced output voltage and current of 66 V and 40 µA and demonstrated a state-of-the-art high power density of 170 µW/cm² at an optimum load resistance of 2.5 MΩ. When mounted on the wrist as a wearable healthcare monitoring device, it successfully detected the movement of tendons and muscles as soon as the fingers were moved and exhibited a corresponding change in voltage response. Additionally, the charging of a capacitor is proven by the PNG under continuous foot tapping, demonstrating its potential to charge energy storage devices by walking or jogging.

具有高功率转换效率的柔性压电纳米发电机（PNG）引起了人们极大的兴趣。在这里，我们提出了基于原始镁 (Mg) 掺杂 GaN (GaN:Mg) 和 GaN:Mg/ZnO 同轴纳米线 (NW) 的可穿戴 PNG，显示出最先进的高压和电流输出。PNG 旨在通过减小 NW 的直径、在 GaN NW 中成功掺入 Mg 作为 p 型掺杂剂以及在 GaN:Mg NW 上沉积 ZnO 壳来抑制内部屏蔽。费米能级钉扎减少了薄纳米线（直径高达 ~30 nm）中的自由载流子。通过调整金属合金催化剂的尺寸，我们获得了直径在 30 到 50 nm 之间的纳米线。为了完全耗尽 NWs 中的自由载流子，在没有活化的情况下加入 Mg，这通过形成非活性的 Mg-H 复合物来增强 GaN:Mg NWs 的电阻。使用原始 GaN:Mg NW 制造的柔性 PNG 的最大输出电压和电流分别为 52 V 和 23 µA。通过在 GaN:Mg NW 上沉积优化厚度为 10 nm 的 ZnO 壳来抑制结电流屏蔽。用 GaN:Mg/ZnO 同轴 NW 制造的 PNG 显示出 66 V 和 40 µA 的增强输出电压和电流，并展示了 170 µW/cm 的最先进的高功率密度²在 2.5 MΩ 的最佳负载电阻下。当作为一种可穿戴的保健监测设备安装在手腕上时，只要手指一动，它就成功地检测到肌腱和肌肉的运动，并表现出相应的电压响应变化。此外，PNG 证明了在连续脚部敲击下电容器的充电，证明了其通过步行或慢跑为储能设备充电的潜力。