Metamaterial route to direct photoelectric conversion

摘要

Photoelectric conversion is of essential importance for harvesting the solar energy and detecting the photonic and optical signals. Conventional technique for photoelectric conversion is based on the mechanism of photo-generated carriers in semiconductors. As it depends on a series of indirect and sophisticated physical processes, the efficiency and wavelength applicability are severely constrained by the materials’ performance and device construction. Here, we propose a novel metamaterial route to convert the optical energy into dc electric energy directly from the carrier drift driven by electric and magnetic field in electromagnetic wave. The metamaterial is composed of magneto-electric coupling metamolecules with two nested meta-atoms. With the excitation of an intense temporally asymmetric Lorentz force in the metamolecule, the free carriers are driven to accumulate at the physical boundary, which generates an apparent static voltage. With the fundamental avoidance of the complex processes in the conventional indirect mechanisms, this innovative paradigm of direct photoelectric conversion supplies a sound strategy for ultrafast photodetection and all-wavelength optoelectronics with high-design freedom.