The Solar Cell That Turns 1 Photon into 2 Electrons

Solar cells are picky. If an incoming photon has too little energy, the cell won’t absorb it. If a photon has too much, the excess is wasted as heat. No matter what, a silicon solar cell can never generate more than one electron from a single photon. Such harsh quantum realities severely limit the conversion efficiency of photovoltaic cells, and scientists have spent decades looking for work-arounds.

Now, researchers at the Massachusetts Institute of Technology’s Center for Excitonics have published a compelling case that the key to greater solar efficiency might be an organic dye called pentacene. In today’s issue of Science Daniel Congreve, Jiye Lee, Nicholas Thompson, Marc Baldo and six others show that a photovoltaic cell based on pentacene can generate two electrons from a single photon—more electricity from the same amount of sun. Scientists have suspected for some time that this might work; today’s paper is proof of concept.

The key is a phenomenon called singlet-exciton fission, in which an arriving photon generates two “excitons” (excited states) that can be made to yield two electrons. Previous researchers had accomplished similar tricks using quantum dots (tiny pieces of matter that behave like atoms) and deep-ultraviolet light. “What we showed here,” Baldo says, in addition to using visible light, “is that [this process] works very, very effectively in organic materials.”  Full Article:

Comments (0)

This post does not have any comments. Be the first to leave a comment below.


Post A Comment

You must be logged in before you can post a comment. Login now.

Featured Product

MORNINGSTAR - GenStar MPPT

MORNINGSTAR - GenStar MPPT

GenStar MPPT is the industry's first fully integrated solar DC charging system, an all-new design with "lithium DNA" from the leader in charge controllers. Out of the box, GenStar is an overachiever-delivering legendary Morningstar quality, efficiency, power and reliability along with the latest in advanced communications and control technologies. All the most installer-requested features are on-board; additional features can be easily added via Morningstar's ReadyBlock expansion technology, with snap-in blocks that provide battery metering and monitoring, signaling and load control, and lithium battery communications/control