The plasmoelectric effect: optically induced electrochemical potentials in resonant metallic structures

The plasmoelectric effect: optically induced electrochemical potentials in resonant metallic structures Matthew T. Sheldon and Harry A. Atwater Thomas J. Watson Laboratories of Applied Physics, California Institute of Technology, MC 128-95, Pasadena, California 91125, USA We describe a strategy for conversion of optical power into DC electrical power using resonant absorption in plasmonic nanostructures. A thermodynamic analysis of the underlying mechanism motivates our description of the phenomenon, which we term the plasmoelectric effect. Power conversion results from the dependence of optically generated heat on shifts of the plasmon resonance frequency that occur with changes of electron density. We model an all-metal device constructed from 10 nm radius silver spheres and predict a characteristic conversion efficiency of 14.3% under 1 kW m-2 intensity, single-frequency radiation. We discuss strategies for enhanced efficiency, broadband power conversion, and further applications of this new class of optoelectronic device. Plasmonic nanostructures display remarkable optical properties arising from