Efficient conversion of mechanical energy in our surrounding environment into electric power has become a promising strategy for meeting the ever-increasing energy consumption of small and distributed electronics. The contact-electrification-based triboelectric nanogenerators are one of the emerging devices to achieve such energy conversion. However, conventional contact electrifications between two insulators are limited by their low current density and alternating current output. Here we report a nanoscale contact electrification induced direct current output based on the flow of electrons from the defect states of the ZnO nanowires-packed film to the contact sliding conductive AFM tip. Combining experimental materials characterization and density functional theory (DFT) calculations, the direct current output is closely related to the concentration of oxygen vacancy defect states on the surface of ZnO nanowires: the higher the oxygen vacancy concentration, the higher the current output. Under optimized conditions, we obtain an ultrahigh current density of ~10⁸ A m^-2, which is several orders of magnitude higher than that of the conventional contact electrification and other effects. This work provides a new route of utilizing defect states contributed contact electrification for realizing nanoscale mechanical energy scavenging.

将我们周围环境中的机械能有效转换为电能已成为一种满足小型和分布式电子产品不断增长的能耗的有前途的策略。基于接触带电的摩擦纳米发电机是实现这种能量转换的新兴设备之一。然而，两个绝缘体之间的常规接触带电受到其低电流密度和交流输出的限制。在这里，我们基于从ZnO纳米线填充薄膜的缺陷状态到接触滑动导电AFM尖端的电子流，报告了纳米级接触带电感应的直流输出。结合实验材料表征和密度泛函理论（DFT）计算，直流输出与ZnO纳米线表面的氧空位缺陷状态浓度密切相关：氧空位浓度越高，电流输出越高。在优化条件下，我们获得了约10的超高电流密度⁸ A m ^-2，比常规的接触带电和其他效果高几个数量级。这项工作提供了一种新的途径，利用缺陷态有助于接触带电实现纳米级的机械能清除。