Characterization and Modeling of Low-Cost Contact-Mode Triboelectric Devices for Energy Harvesting

In this paper we investigate the effect of the contact force in Contact-Mode Tribo Electric Devices (CM-TED). In this kind of devices, the generated output voltage and the electrical energy harvested from mechanical impacts depend on the contact force. The number of impacts and the contact force influences also the surface charge density of the triboelectric layers of CM-TED. This is confirmed by the measurements carried out on the low-cost CM-TED prototypes we realized using commercial silicone as triboelectric material. The effect of the impact force has been included into a device model suitable for both dielectric-to-dielectric and contact-to-dielectric triboelectric devices. The model predicts the output voltage and power at given conditions and it can be used to design ultra-low cost triboelectric energy harvesters. The realized prototypes provide up to 5.5 mu W when subjected to repetitive impacts with a contact force of 65N.