A new experiment shows that the energy conversion rate of solar cells will increase greatly, foreign media reported.There is an absolute limit to the overall efficiency of any conventional silicon-based solar cell, in part because each photon of light can produce only one electron, even though it carries twice as much energy as the electron needs.But now researchers have demonstrated a way to make high-energy photons react with silicon to produce two electrons, opening the door to new solar cells that are far more efficient than ordinary solar cells.

Writing in the journal nature, the MIT and Princeton research teams say that while traditional silicon cells have a theoretical maximum solar conversion efficiency of about 29.1 percent, new methods they have developed over the past few years could break that limit by several percentage points.

The theory of the new technology has been around for decades, but six years ago, some members of the team first demonstrated that it could work.The key to splitting a photon’s energy into two electrons lies in a class of “excited states” of material called excitons, the researchers said.In these exciton materials, they have energy packets that travel like electrons in a circuit, but with completely different properties from electrons.In this case, they tested a process called singlet fission, which is how light energy splits into two independently moving energy packets.

“Excited state” materials first absorb photons to form excitons, which then undergo rapid fission into two excited states, each with half the energy of the original state.But a new problem arises: how to couple the two energies into silicon, a non-excitonic material.To do this, the team tried and succeeded in coupling the energy of the exciton layer into a substance called a quantum dot.But researchers say the key question now is how to fuse the newly coupled quantum dots into the chemistry of silicon, and they’re trying to figure out how best to do it.