Iridium-based selective emitter for thermophotovoltaics

A research group at the Helmholtz Center Hereon, headquartered in Geesthacht near Hamburg, Germany, has joined forces with the Technical University of Hamburg and the Danish University of Aalborg to develop a selective emitter based on the precious metal iridium for use in thermophotovoltaics. The results have been published in Advanced Materials.
Even though an economically viable application on a large scale seems to be difficult to realize, some research institutions continue to dedicate themselves to thermophotovoltaics, i.e. the harnessing of heat sources for electricity generation with solar cells. This requires a selective emitter that allows only the short-wavelength photons that can be used by a solar cell to pass through, while suppressing the long-wave photons. It is conceivable that this principle could be used to utilize the thermal radiation from industrial plants or from heat accumulators that have previously been loaded by using wind or solar power.
Because of the temperatures involved, however, the requirements for heat resistance are very high. According to the research group, the emitter now developed, which is made of iridium and hafnium oxide, »retains its function completely over 100 hours at 1,000 degrees Celsius.« This is »an important step in the progress of thermophotovoltaics.«
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