Based on decades of solar cells research - one formula has been considered very important which is the absolute limit to the efficiency of such devices in converting sunlight into electricity. Typically known as Shockley-Queisser efficiency limit whereby it posits that the conversion efficiency can never exceed 34% for a single optimised semiconductor junction.
Interestingly researchers at Massachusetts Institute of Technology (MIT) have managed to demonstrate that there is a way to blow past such a limit as easily as today's jet fighters zoom through the sound barrier.
The MIT researchers work appears in Science, which is co-authored by graduate students including Daniel Congreve, Nicholas Thompson, Eric Hontz and Shane Yost, alumna Jiye Lee '12 and Professors Marc Baldo and Troy Val Voorhis.
The idea behind the barrier-busting technique has been known academically since the 1960s, as stated by Baldo, a professor of electrical engineering at MIT. However, at the time it was an obscure idea which nobody had succeeded in putting into practice. The MIT team was able for the first time to perform a successful Proof-of-Principle (PoP) experimentation, which is known as singlet exciton fission. Exciton is the excited state of a molecule after absorbing energy from a photon.
As stated by Congreve, the theoretical basis of the work was laid a long time ago, but, unfortunately, nobody had been able to realise it in a real and functioning system. He states - "In this system, everyone knew you could, they were just waiting for someone to do it."
Since the research, above, was the first ever PoP subsequently the team has not yet optimised the energy-conversion efficiency of the system, which remains less then 2%. However, ensuring efficient optimisation should be relatively straightforward, as stated by Thompson - "There appears to be no fundamental barrier."
Nowadays commercial solar panels have an efficiency of at least 25%, but as stated by Baldo a Silicon (Si) solar cell harnessing singlet fission should make it feasible to achieve efficiency of more then 30%. As described it is a classed as a huge leap in a field which is typically slow and small incremental progress.
Solar panel efficiencies can also be improved by stacking different solar cells together, but in combining makes the solar cells expensive when using conventional solar cell materials. Alternatively the new MIT technology provides promise as an inexpensive coating on solar cells.
The research used a known material, but the team is now exploring new materials which may perform the same trick even better, as stated by Baldo - "The field is working on materials that were chanced upon," - but because the principles are better understood, then the researchers can begin exploring alternatives in a more systematic manner. Original article available here
As with similar type of studies the future potential of nanotechnology coatings has been handsomely sold. As stated previously, DCN Corp strongly believes it can supersede, and so going forward if you and/or your colleagues are interested in making an alternative process reality - please ensure to contact the company as soon as practicably possible.