'Squeezing' near-field thermal emission for ultra-efficient high-power thermophotovoltaic conversion.

ABSTRACT: 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(2) with ~47% efficiency at 300?nm vacuum gap; at 2100?°K, 24?W/cm(2) with ~57% efficiency at 200?nm gap; and, at 3000?°K, 115?W/cm(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.

SUBMITTER: Karalis A 

PROVIDER: S-EPMC4929479 | biostudies-literature | 2016 Jul

REPOSITORIES: biostudies-literature