A team of engineers from Massachusetts Institute of Technology (MIT) has for the first time exhibited a device based on a technique that enables solar cells to overcome a theoretically predicted cap on the amount of sunlight they can convert into electricity.
The new technique developed by the MIT engineers is called solar thermophotovoltaics (STPVs), which is basically an alternative method to change the energy first before it can generate electricity, Tech Times reported.
Currently, nearly all solar cells have to deal with the Shockley-Queisser Limit, which places a limitation on the amount of power produced by a particular device founded on the light frequencies landing on a surface. For most silicon-based solar cells that maximum efficiency is roughly 32 percent. However, several cells employ multiple layers or endeavor to convert absorbed heat into electricity to facilitate some extra percent.
In this context, the team from MIT has developed a somewhat different technique. The new device developed by the team first absorbs heat and light from sunlight, making use of a special layer capable to re-emitting radiation at specific wavelengths that are better suited to the nearby solar cell, a study published in Nature Energy stated.
That specific layer is composed of nanophotonic crystals, which, when heated, give out specific frequencies of light. The device carefully tweaks the crystals to generate the right frequency factors to create radiation, which the solar cells absorb more readily. This, in turn, improves the device's efficiency in generating more power from heat.
According to the researchers, the conventional photovoltaics (PV) have a theoretical energy cap, but this can be breached by the STVPs. They have calculated that the STPVs, which use traditional solar cells in addition to sheets of high-tech materials, can even exceed the efficiency limit by twofold, David Bierman, lead study author who is a doctoral student at MIT, said explaining their new theory.
The engineers have demonstrated that the STPV device certainly possess the aptitude to translate solar energy into electricity at a superior degree compared to a device using only a low-efficiency PV cell.
According to Bierman, so far, plenty of work in this field has been proof-of-concept demonstrations, and this is the first time they have succeeded in "putting something between the sun and the PV cell to prove the efficiency" of the thermal system.
Watch the MIT video on making solar panels more efficient below: