A new technique to produce solar cells might one day yield devices that boast significantly greater efficiency — long a holy grail in the development of commercial solar panels.
Researchers at MIT say they've successfully harnessed an obscure technique, called "singlet exciton fission," that would reduce the amount of sunlight wasted as heat instead of being converted to electricity. In a typical solar cell, each photon of sunlight hitting the cell knocks loose one electron, to kickstart the process of energy conversion. In this new research, however, each photon knocks two electrons loose — making the process of solar energy generation more efficient.
The process behind the research is relatively simple: researchers successfully coated solar cells with pentacene, an organic compound capable of generating two electrons from one photon.
Their technique will allow solar cells to transcend that limit
The finding is particularly important because it may break what has, until now, been considered a fundamental barrier in solar energy efficiency: a calculation, known as the Shockley-Queisser limit, which posits that solar conversion will never exceed an efficiency level of 33.7 percent. And right now, top-notch commercial solar panels max out at around 25 percent efficiency.
According to the MIT team, their technique will allow solar cells to transcend this limit. Unfortunately, that big moment isn't here just yet: the research is still in its early stages, with a proof-of-principle that maxes out at 2 percent efficiency. And while the researchers don't elaborate on exactly how they'll boost those efficiency levels, study co-author Nicholas Thompson said that "there appears to be no fundamental barrier" to making it happen.