Effect of Impurity/Humidity on Liquid-Crystal-Enhanced Electret Vibration Energy Harvester

Abstract

In this report, the liquid-crystal-enhanced electret vibration energy harvester has been realized for the first time. The effect of impurities and humidity on resistivity of nematic liquid crystal (LC) was examined. By suppressing the ionic impurities and humidity absorption in the operation environment, extremely-high resistivity of $10^{16}\Omega \mathrm{c}\mathrm{m}$ can be obtained. By introducing LC between the electrets/electrodes, 7-times higher output power compared to the air gap has been obtained for over 40 hours. Furthermore, the LC alignment near the electrode gap is also investigated with Fourier-transform infrared (FT-IR) spectrometry. The power generation model is proposed based on the present finding, and the simulation results agree well with the experimental data.