Modeling the Effects of a Protective Film for Spontaneously-Polarized Electrets on the Power Harvesting Performance of a Wind Energy Harvester

One bottleneck for developing electret-based energy harvesters is the electret charging process. This increases production time, and raises fabrication cost and safety concerns. Spontaneously-polarized electrets, as alternatives, do not need any charging process. However, the main drawback is their susceptibility to UV-Vis light. This is a big concern for harvesters in open environments that cannot be kept in perfect darkness. Focusing on a leaf-like wind energy harvester, this paper analytically examines the effects of covering SP electret with a protective layer on performance characteristics of the harvester. This layer is not only an optical barrier, but can also act as a mechanical stopper to determine the minimum gap distance and prevent direct contact between the electret and the counter-electrode in a gap-closing motion.