19 Apr 2013:
New Solar Cell Process
Achieves Record Efficiency, MIT Says
Researchers at the Massachusetts Institute of Technology (MIT) say they have achieved a major breakthrough in the conversion of sunlight into electricity
, surpassing what was long believed to be an absolute limit to the efficiency of solar cell devices. While the process used in the typical photovoltaic (PV) cell process knocks loose one electron inside the PV material to produce an electrical current — but wastes any excess energy carried by a photon — a new process described in the journal Science
utilizes that extra energy to produce two electrons. That exploits so-called singlet exciton fission and makes the process far more efficient, creating more electrical energy. An exciton is the excited state of a molecule after absorbing energy. While the material used in the organic solar cell, known as pentacene, was previously known to produce two so-called excitons from one photon, researchers say this is the first time anyone has demonstrated the principle within a photovoltaic device. While the typical solar panel achieves efficiencies no greater than 25 percent, the scientists believe this process can be utilized to achieve efficiencies of more than 30 percent.