Professor Marin Soljacic of MIT Physics Department described progress in using photonic crystals to produce tailored infrared spectra for photovoltaic energy at the Materials Day Symposium, hosted by the Materials Processing Center Oct. 23, 2013. The daylong symposium was held in Little Kresge Auditorium on the MIT campus.
“We can tailor the emission of a black body almost at will,” Soljacic said, explaining how a periodic array of holes sharply modifies the wavelengths emitted by a material such as tungsten.
“By tailoring the nanostructure, we can tailor the laws of physics, at least as far as light is concerned, almost at will,” Soljacic said. The process pairs a periodic lattice of materials with different indexes of refraction, one high index and one low index. The material acts as a perfect mirror. Photonic crystals can increase efficiency of a solar thermophotovoltaic device, and they also are thought to be one of the more promising candidates for integration of photonics into semiconductors.
Soljacic also reported on a matchbox size propane, or butane, powered thermophotovoltaic power generator that can provide 1 watt of electricity at about 3 percent efficiency. He hopes to achieve 10 to 15 percent efficiency in the next generation.
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