What material property is critical for maximizing charge retention in a triboelectric material?

The critical material property for maximizing charge retention in a triboelectric material is its dielectric constant and resistivity. A high dielectric constant allows the material to store more electrical energy for a given voltage, effectively increasing the amount of charge it can hold. The resistivity, specifically a high resistivity, is equally important because it determines how well the material can prevent the leakage or dissipation of the stored charge. A material with high resistivity minimizes the flow of charge through the material itself and across its surface, reducing charge recombination with oppositely charged species from the environment or from the other triboelectric material. In simpler terms, a high dielectric constant acts like a larger container for charge, and high resistivity acts like a good insulator, preventing the charge from leaking out of the container. For example, materials like Teflon and certain ceramics have high resistivity, which allows them to retain triboelectric charges for extended periods, making them suitable for TENG applications. Conversely, materials with low resistivity, such as metals, quickly dissipate charge, rendering them unsuitable for charge retention in TENGs unless properly insulated.