Anomalous Output Performance Enhancement of Triboelectric Nanogenerators by Manipulation of Surface Molecular Dipoles

Since the invention of triboelectric nanogenerators (TENGs), numerous strategies have been proposed to boost their performance by altering the triboelectric materials, typically centered on increasing work function disparities or effective contact areas. However, in this study, we introduce a novel approach that significantly enhances output performance through the manipulation of surface molecular dipoles, a departure from conventional methods.<br/>In our research, we demonstrate a significant improvement in TENG output performance by manipulating surface dipoles, achieved by bonding copper ions to the oxygen-containing functional groups on the surface of graphene oxides. This bonding causes a reversal in the orientations of surface molecular dipoles, resulting in the enhancement of TENG output. Remarkably, the variations in TENG output performance due to these surface modifications are contrary to what would be predicted based solely on differences in work functions, as determined by Kelvin probe force microscopy. This observation suggests that factors beyond work functions play a pivotal role in governing TENG performance. We propose a self-bias-enhancement model by surface dipoles and further testifies it by polling processes. This mechanism is expected to have universal applicability to other materials aimed at enhancing the performance of TENGs and self-powered devices.