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SJTU Research Team Co-found Direct-current Generated by Nanocontact

December 14, 2017      Author: Zhang Yifan

On Dec.11, the world-leading academic journal Nature Nanotechnology published online a research paper titled "Direct-current triboelectricity generation by a sliding Schottky nanocontact on MoS2multilayers", of which the correspondent authors are Professor Thomas Thundat and Jun Liu, members of Shanghai Jiao Tong University (SJTU). The research team found a new triboelectric charge carrier transport mechanism in two-dimensional MoS2 materials using conductive atomic force microscopy (C-AFM), making a major breakthrough in nano-friction power generation. Within 24 hours after the online publication of the paper, it was reported by multiple international media outlets such as Science Daily, Phys.org, EurekAlert, R&D Magazine, Twitter, CNN, and CBC.

The paper shows 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. The research team demonstrates 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. They 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.