Photo-stimulated charge transfer in contact electrification coupled with plasmonic excitations

Photo-stimulated triboelectric generation coupled with plasmonic effects occurring between TiO2 and Au during instantaneous friction is described. The output voltages of the triboelectric nanogenerator increase under UV light illumination and decrease under visible light, eventually reaching zero at a light intensity of 480 mW/cm(2). Based on the electron thermionic emission, two models affecting the charge transfer between the TiO2 and the Au are suggested. They are the UV light-induced modification of TiO2 and the generation of the hot electrons in Au by the visible light. This study is fundamentally important for understanding triboelectric effects coupled with plasmonic effects, which will provide a new route for photodetectors and energy-harvesting devices in diverse environments.