Metamaterial Enhanced Thermophotovoltaic Converter

摘要

A thermophotovoltaic (TPV) converter includes a spectrally-selective metamaterial emitter and an associated “matched” photovoltaic (PV) cell. The PV cell has an optimal conversion spectrum (i.e., the wavelength range of in-band photons efficiently converted into electricity). The metamaterial emitter is fabricated with bull's eye (circular target-shaped) structures made up of concentric circular ridges that are set at a fixed grating period roughly equal to the associated optimal conversion spectrum. When the emitter is heated to a high temperature (i.e., above 1000° K), thermally excited surface plasmons generated on the concentric circular ridges produce a highly-directional radiant energy beam having a peak emission wavelength that is roughly equal to the fixed grating period and is directed onto the PV cell. The metamaterial emitter is optionally provided with multiple bull's eye structures in a multiplexed (overlapping) pattern and with different grating periods to produce a broad emission spectrum overlapping the optimal conversion spectrum.

主权项

1. A thermophotovoltaic (TPV) converter comprising:
a spectrally-selective metamaterial emitter including one or more bull's eye structures disposed on a solid base substrate, each of said one or more bull's eye structures including a plurality of concentric circular ridge structures separated by intervening circular grooves such that each adjacent pair of ridge structures is separated by a fixed grating period; and a photovoltaic (PV) cell fixedly disposed to receive radiant energy generated by said spectrally-selective metamaterial emitter, said PV cell including means for converting in-band photons at a higher efficiency than out-of-band photons, said in-band photons having associated first wavelengths within an optimal conversion wavelength range, and said out-of-band photons having associated second wavelengths outside of said optimal conversion wavelength range, wherein said one or more bull's eye structures are configured such that, when the metamaterial emitter is heated to a temperature above 1000° K, radiant energy is emitted from said one or more bull's eye structures having a peak emission wavelength that is within said optimal wavelength range, whereby said spectrally-selective metamaterial emitter is matched to the PV cell.