Micro pattern of charge in PTFE electret for energy harvesters

This paper presents a novel fabrication process to pattern the charge in electret film for vibration energy harvester and sensor applications. Electret material is charged with pattern through a mask layer, and is not required to be etched, which simplifies the pattern process. The line width of the pattern is determined by photolithography process. Compared with previously reported techniques[1,2,3], PTFE electret material, which is inexpensive and has very high bulk resistivity, is used for the experiment. Experiment results show that the surface potential on the patterned charge zone of PTFE film is higher than -200V when the line width reaches 20μm. A demo electrostatic vibration energy harvester is built by using the pattern technique and tested.