The direct conversion of mechanical energy into electricity by nanomaterial-based devices offers potential for green energy harvesting^1,2,3. A conventional triboelectric nanogenerator converts frictional energy into electricity by producing alternating current (a.c.) triboelectricity. However, this approach is limited by low current density and the need for rectification². Here, we show that continuous direct-current (d.c.) with a maximum density of 10⁶ A m⁻² can be directly generated by a sliding Schottky nanocontact without the application of an external voltage. We demonstrate this by sliding a conductive-atomic force microscope tip on a thin film of molybdenum disulfide (MoS₂). Finite element simulation reveals that the anomalously high current density can be attributed to the non-equilibrium carrier transport phenomenon enhanced by the strong local electrical field (10⁵−10⁶ V m⁻²) at the conductive nanoscale tip⁴. We hypothesize that the charge transport may be induced by electronic excitation under friction, and the nanoscale current−voltage spectra analysis indicates that the rectifying Schottky barrier at the tip–sample interface plays a critical role in efficient d.c. energy harvesting. This concept is scalable when combined with microfabricated or contact surface modified electrodes, which makes it promising for efficient d.c. triboelectricity generation.

通过基于纳米材料的设备将机械能直接转化为电能，为收集^1,2,3的绿色能源提供了潜力。常规的摩擦纳米发电机通过产生交流（ac）摩擦电将摩擦能转化为电能。但是，这种方法受到电流密度低和整流^2的限制。在此，我们表明，通过滑动肖特基纳米接触可以直接产生最大密度为10 ⁶  A m ^-2的连续直流电（dc），而无需施加外部电压。我们通过在二硫化钼（MoS ₂）。有限元模拟显示，异常高的电流密度可归因于导电纳米级尖端^4上的强局部电场（10 ⁵ -10 ⁶  V m ^-2）所增强的非平衡载流子传输现象。我们假设电荷传输可能是由摩擦力下的电子激发引起的，并且纳米级电流电压谱分析表明，尖端-样品界面处的整流肖特基势垒在有效的直流能量收集中起着关键作用。当与微型加工或接触表面改性的电极结合使用时，该概念可扩展，这使其有望有效地产生直流摩擦电。