Tribovoltaic Devices based on Sliding Contact TiO2 Films

Tribovoltaic (TV) devices are motion-based energy harvesters with high local current densities that can be generated. Debate remains surrounding the fundamental charge generation mechanism of TV devices. Here, we study the charge generation mechanism for TV device fabricated from thin films of the world’s most common oxides, TiO2. We compare the TV performance under contact with metals of varying work functions, contact areas, and applied pressure. The resultant current density shows little correlation with the work function of the contact metal and a strong correlation with the contact area. Considering other effects at the metal−semiconductor interface, the thermoelectric coefficients showed a clear correlation with the tribovoltaic current density. We put in front the need to consider a variety of mechanisms to understand the tribovoltaic effect and design future exemplary TV devices.