Conversion of broadband energy to narrowband emission through double-sided metamaterials

In this paper, an energy harvesting/re-radiating device is proposed to realize high efficiency energy conversion in the solar thermo-photovoltaic system. Such device consists of double-sided metamaterials which are assembled by a broadband absorber working in the major solar spectrum, and a back-by-back narrowband emitter working in the infrared band. It is theoretically proved that most of solar light (from 0.28 μm to 4 μm) can be collected, and then, converted to a sharp emission at the maximal response energy level (~0.4 eV) of photovoltaic cells in thermal equilibrium state. The impact of high temperature (as large as 966 K) and the parasitic radiation on the performance is discussed and compensated by geometric optimization.