Coupling electrostatic induction and global electron circulation for constant-current triboelectric nanogenerators

Abstract

Obtaining direct-current (DC) output is important to triboelectric nanogenerator (TENG) technology. The working mechanism of a TENG is a fixed number of electrons periodically oscillating between electrodes through a load circuit. For most DC-TENGs, unipolar output is realized by using local-rectification, which is introducing rectifying devices to the load circuit, and the essence of periodical electron oscillation between electrodes is not changed. In this work, a constant-current TENG with global electron-circulation is demonstrated. The basic unit of our TENG only consists of a metal induction layer (MIL) connected with an electronic load through two rectified PN-junctions. The MIL-load loop is in an electric neutrality state. The force driving the global electroncirculation in the MIL-load loop is the electrostatic force introduced from an external position-variable charged layer. The periodic motion of the charged layer leads to a unidirectional electron-circulation in the MIL-load loop. A stable constant current can be obtained by increasing the number of parallel MIL units. This constantcurrent TENG can be used to directly drive LEDs without flicker and to directly drive electronic devices. Because no contact is made between the charged layer and the MIL units, the operational life of the TENG is effectively extended.