Abstract
This paper proposes a new electret with high surface potential and high thermal resistance, which is made of nano-porous silicon dioxide (SiO2). Electrical charge density in the nano-porous SiO2 is higher than that in a normal (i.e., nonporous) SiO2 because there are many voids in the nano-porous SiO2 and the interface between void and SiO2 traps electrical charges strongly. Therefore, decrease rate of the trapped charge density in the nano-porous SiO2 is lower than that of normal SiO2. Since SiO2 is thermally stable, thermal stability of the electrical charge in nano-porous SiO2 electret is better than that in a polymer electret. Output power generated by vibration energy harvesting using the nano-porous SiO2 electret is also larger than that using the normal SiO2 or polymer electret.
