Atomic-crystal transition metal dichalcogenides Schottky triboelectricity nanogenerator with ultrahigh direct-current density

Direct-current triboelectric nanogenerators (DC-TENGs) have recently become more attractive to convert mechanical energy into electricity due to their high current density with no need for rectification. Interfacial charge transfer, induced by the sliding contact on semiconductor materials, is critical to generate DC output but usually limited by the interfacial properties. Here, we report Schottky DC-TENGs based on the atomic-crystal transition-metal dichalcogenides (TMDs) with single crystallinity, monolayer thickness and atomic flatness to enhance the interfacial charge transfer. A record-high current density of 10¹⁰ A/m², two orders of magnitude higher than the state-of-the-art performance, can be directly generated by sliding a conductive-atomic force microscope tip on an atomic-crystal molybdenum disulfide. Density functional theory calculation and finite element simulation reveal that this ultrahigh current density can be attributed to the enhanced interfacial property owing to the atomic flatness of TMDs and strong local electrical field of nanoscale tip. We further demonstrate their excellent scalability by a high-crystalline monolayer film with sliding electrode. This work may guide and accelerate the development and application of high-performance DC-TENGs.