Inorganic electret with enhanced charge stability for energy harvesting

We report a new surface treatment of inorganic electret materials which enhances the charge stability. Coating the surfaces with 1H, 1H, 2H, 2H - perfluorodecyltrichlorosilane (FDTS) makes the electret surface more hydrophobic which improves the surface charge stability under high humidity conditions. Thermal tests show that the thermal stability of charge in the inorganic electrets is also much better than that of polymer materials such as CYTOP. A demonstrator device with SiO₂ electrets shows promising results for energy harvesting applications.