The origin of highly efficient selective emission in rare-earth oxides for thermophotovoltaic applications.
Rare-earth oxide materials emit thermal radiation in a narrow spectral region, and can be used for a variety of different high-temperature applications, such as the generation of electricity by thermophotovoltaic conversion of thermal radiation. However, because a detailed understanding of the mechanism of selective emission from rare-earth atoms has so far been missing, attempts to engineer selective emitters have relied mainly on empirical approaches. In this work, we present a new quantum thermodynamic model to describe the mechanisms of thermal pumping and radiative de-excitation in rare-earth oxide materials. By evaluating the effects of the local crystal-field symmetry around a rare-earth ion, this model clearly explains how and why only some of the room-temperature absorption peaks give rise to highly efficient emission bands at high temperature (1,000-1,500 degrees C). High-temperature emissivity measurements along with photoluminescence and cathodoluminescence results confirm the predictions of the theory.
Department of Physics, University of Lecce, Campus Universitario, Via Arnesano, 73100 Lecce, Italy.
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D003198:Computer Simulation; D011211:Electric Power Supplies; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D006358:Hot Temperature; D008422:Materials Testing; D008674:Metals, Rare Earth / Q000737:chemistry* / Q000528:radiation effects; D008956:Models, Chemical; D010087:Oxides / Q000737:chemistry* / Q000528:radiation effects; D010777:Photochemistry / Q000295:instrumentation / Q000379:methods*; D011210:Power Plants
D008674:Metals, Rare Earth; D010087:Oxides