A new approach to harvesting solar energy, developed by MIT researchers, could improve efficiency by using sunlight to heat a high-temperature material whose infrared radiation would then be collected by a conventional photovoltaic cell. This technique could also make it easier to store the energy for later use, the researchers say.
Researchers at MIT have developed a solar thermophotovoltaic device that experimentally demonstrates a three-fold increase in energy conversion efficiency. Their device builds upon solar thermophotovoltaic technologies, adding a nanophotonic absorber-emitter that is tuned for optimal collection of sunlight and thermal emission above the photovoltaic band gap.
This basic concept has been explored for several years, since in theory such solar thermophotovoltaic (STPV) systems could provide a way to circumvent a theoretical limit on the energy-conversion efficiency of semiconductor-based photovoltaic devices. That limit, called the Shockley-Queisser limit, imposes a cap of 33.7 percent on such efficiency, but Wang says that with TPV systems, “the efficiency would be significantly higher — it could ideally be over 80 percent.”
There have been many practical obstacles to realizing that potential; previous experiments have been unable to produce a STPV device with efficiency of greater than 1 percent. But Lenert, Wang, and their team have already produced an initial test device with a measured efficiency of 3.2 percent, and they say with further work they expect to be able to reach 20 percent efficiency — enough, they say, for a commercially viable product.]
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Operating principle and components of the NARO–STPV.
Nature Nanotechnology - A nanophotonic solar thermophotovoltaic device
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Researchers at MIT have developed a solar thermophotovoltaic device that experimentally demonstrates a three-fold increase in energy conversion efficiency. Their device builds upon solar thermophotovoltaic technologies, adding a nanophotonic absorber-emitter that is tuned for optimal collection of sunlight and thermal emission above the photovoltaic band gap.
This basic concept has been explored for several years, since in theory such solar thermophotovoltaic (STPV) systems could provide a way to circumvent a theoretical limit on the energy-conversion efficiency of semiconductor-based photovoltaic devices. That limit, called the Shockley-Queisser limit, imposes a cap of 33.7 percent on such efficiency, but Wang says that with TPV systems, “the efficiency would be significantly higher — it could ideally be over 80 percent.”
There have been many practical obstacles to realizing that potential; previous experiments have been unable to produce a STPV device with efficiency of greater than 1 percent. But Lenert, Wang, and their team have already produced an initial test device with a measured efficiency of 3.2 percent, and they say with further work they expect to be able to reach 20 percent efficiency — enough, they say, for a commercially viable product.]
Operating principle and components of the NARO–STPV.
Nature Nanotechnology - A nanophotonic solar thermophotovoltaic device
Read more »
