14 DAY TRIAL // In a press release issued on the website of the Massachusetts Institute of Technology (MIT), researchers describe a new approach to harvesting solar power, which they say is more efficient than the ones already used, and bound to make it easier to store this type of energy and use it at a later time.
The MIT scientists who worked on developing this new approach detail that their method boils down to harvesting sun energy through both heat and light.
They explain that conventional silicon-based solar cells fail to make the most of the energy of all the photons coming their way, and that, consequently certain wavelengths of light are pretty much wasted.
In an attempt to solve this problem, the MIT researchers placed an intermediate material, which they call a two-layer absorber-emitter device, between the sunlight and the photovoltaic cell.
This device, which is made of new materials such as carbon nanotubes and photonic crystals, works by collecting energy from a broad spectrum of sunlight and getting hot as a result of its doing so.
Once the device heats up to a considerable extent, it emits infrared radiation whose wavelength allows it to be picked up and harvested by the run-off-the-mill photovoltaic cell.
While toying with a test device inside the laboratory, the scientists managed to make it reach a measured efficiency of 3.2%. They say that, in time, the device's efficiency could be increased to 20%.
Once this happens, this new means of harvesting sun energy through heat and light could be employed to develop commercial products.
“This work is a breakthrough in solar thermophotovoltaics, which in principle may achieve higher efficiency than conventional solar cells because STPV [solar thermophotovoltaic] can take advantage of the whole solar spectrum,” Zhuomin Zhang commented on the MIT researchers' achievements.
“This achievement paves the way for rapidly boosting the STPV efficiency,” the Georgia Institute of Technology researcher, who was not involved in this study, went on to add.
A paper detailing the work of the MIT scientists was published in the journal Nature Technology.