‘Squeezing’ near-field thermal emission for ultra-efficient high-power thermophotovoltaic conversion
Author(s)Karalis, Aristeidis; Joannopoulos, John
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We numerically demonstrate near-field planar ThermoPhotoVoltaic systems with very high efficiency and output power, at large vacuum gaps. Example performances include: at 1200 °K emitter temperature, output power density 2 W/cm[superscript 2] with ~47% efficiency at 300 nm vacuum gap; at 2100 °K, 24 W/cm[superscript 2] with ~57% efficiency at 200 nm gap; and, at 3000 °K, 115 W/cm[superscript 2] with ~61% efficiency at 140 nm gap. Key to this striking performance is a novel photonic design forcing the emitter and cell single modes to cros resonantly couple and impedance-match just above the semiconductor bandgap, creating there a ‘squeezed’ narrowband near-field emission spectrum. Specifically, we employ surface-plasmon-polariton thermal emitters and silver-backed semiconductor-thin-film photovoltaic cells. The emitter planar plasmonic nature allows for high-power and stable high-temperature operation. Our simulations include modeling of free-carrier absorption in both cell electrodes and temperature dependence of the emitter properties. At high temperatures, the efficiency enhancement via resonant mode cross-coupling and matching can be extended to even higher power, by appropriately patterning the silver back electrode to enforce also an absorber effective surface-plasmon-polariton mode. Our proposed designs can therefore lead the way for mass-producible and low-cost ThermoPhotoVoltaic micro-generators and solar cells.
DepartmentMassachusetts Institute of Technology. Institute for Soldier Nanotechnologies; Massachusetts Institute of Technology. Department of Physics; Massachusetts Institute of Technology. Research Laboratory of Electronics
Nature Publishing Group
Karalis, Aristeidis, and J. D. Joannopoulos. “‘Squeezing’ near-Field Thermal Emission for Ultra-Efficient High-Power Thermophotovoltaic Conversion.” Scientific Reports 6.1 (2016): n. pag. © 2017 Macmillan Publishers Limited
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