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Rare-earth selective emitters for high efficiency TPV systems

Rare-earth selective emitters for high efficiency TPV systems address the major limiting factor for the efficiency of TPV cells: the broad emission spectrum from the heat source. Photons with energy smaller than the band gap of semiconductor PV materials cannot be absorbed, while for those with energy much greater than the band gap the excess energy is lost to heat instead of generating electricity. Although there is nothing we can do to change the solar spectrum, for thermal sources of TPV systems we may engineer the thermal emission spectrum by using certain coatings called "selective emitters." Using this approach, the broad blackbody emission spectrum can be condensed to a much narrower band that optimally matches the absorption spectrum of semiconductor TPV cells. In particular, we are investigating rare-earth ceramic selective emitters such as Yb and Er compounds to match the absorption of Si and Ge TPV cells. We are also engineering the microstructures of these compounds to manipulate photons for enhanced selective emitting performance.

Faculty contact: Jifeng Liu