Researchers at the Massachusetts Institute of Technology (MIT) published a paper last week in the journal Nature Energy describing how they built a working solar thermophotovoltaic device (STPV) that pushes solar cells through a theoretically predicted ceiling on how much sunlight they can convert into electricity. With this exciting new technology, the scientist show the potential of how solar modules can generate even more energy than theoretically determined by harnessing some of the module’s wasted heat.
The Shockley-Queisser Limit is commonly accepted as an absolute theoretical limit on traditional solar cell efficiency for energy conversion. Single-layered silicon PV cells—the type of cells most widely used in today’s solar modules—has an upper limit of 32 percent. However, researchers are finding ways to increase this overall efficiency by using multiple layers of cells by converting thermal heat to light which in-turn can be used help increase the overall output of the PV cell layer. This method is known as STPVs, which the MIT team used in their study.
A traditional solar cell converts sunlight into electricity while producing a lot of wasted heat energy. The MIT team introduces a new material layer to the solar cell structure, which enables the device to absorb the heat energy and convert it into light and at the same time helps cool the solar module which helps improve the PV cell layer efficiency. The converted light energy is produced at the correct wavelengths for optimal PV electric generation. This cell configuration and process improves the overall efficiency. The technology to improved efficiency is using a layer of high-tech materials called nanophotonic crystals that can be designed and configured to emit precisely determined wavelengths of light when heated.
This new exciting technology could double the amount of power generated by solar modules without dramatically increasing cost. Soon, solar arrays can be placed on homes with half as many solar modules as are currently required with traditional PV technology! This will also provide a compelling reason for owners of existing PV electric systems to replace their older solar modules with newer STPV modules and double their existing annual electric power production!
More info: Wikipedia Thermophotovoltaic