Plasmoelectric potentials in metal nanostructures

Abstract

The conversion of optical power to an electrical potential is of general interest for energy applications, and is typically obtained via optical excitation of semiconductor materials. Here, we introduce a new method using an all-metal geometry, based on the plasmon resonance in metal nanostructures. In arrays of Au nanoparticles on an indium-tin-oxide substrate and arrays of 100-nm-diameter holes in 20-nm-thick Au films on a glass substrate, we show negative and positive surface potentials during monochromatic irradiation at wavelengths below or above the plasmon resonance respectively. We observe such plasmoelectric surface potentials as large as 100 mV under 100 mW/cm^2 illumination. Plasmoelectric devices may enable development of entirely new types of all-metal optoelectronic devices that can convert light into electrical energy.