PDMS-based flexible energy harvester with Parylene electret and copper mesh electrodes

Abstract

Currently, most vibrational energy harvesters have rigid and resonant structures to scavenge kinetic energy from periodic motion in specific directions. However, in some situations the motion is random in amplitude, frequency, and direction; or the targeted energy sources apply direct deformation or displacement to the harvesters. In these applications, flexible energy harvesters that are light, flat, and conformable to arbitrary 3D surfaces of the sources are desired to scavenge the energy from device deformation, rather than the motion of a moving mass. Therefore we propose and demonstrate a PDMS-based flexible energy harvester with Parylene-C electret that can be attached to deformable surfaces. Furthermore, copper mesh is embedded in the flexible electrodes for robust electrode metallization as compared with traditional sputtered metal thin films. The fabricated harvesters achieved net output power of 2.2 μW, area power density of 2.2 μW cm−2, and volume power density of 22 μW cm−3 at the maximum test frequency of 20 Hz. Power generation by finger tapping and bending was demonstrated. Such harvesters have the potential for wearable and implantable electronic applications.