Most simple solar cells handle the bluish hues of the electromagnetic spectrum inefficiently. This is because blue photons — incoming particles of light that strike the solar cell — actually have excess energy that a conventional solar cell can’t capture.
(Phys.org) —Getting the blues is rarely a desirable experience—unless you’re a solar cell, that is.
Scientists at the U.S. Department of Energy’s Argonne National Laboratory and the University of Texas at Austin have together developed a new, inexpensive material that has the potential to capture and convert solar energy—particularly from the bluer part of the spectrum—much more efficiently than ever before.
Most simple solar cells handle these bluish hues of the electromagnetic spectrum inefficiently. This is because blue photons—incoming particles of light that strike the solar cell—actually have excess energy that a conventional solar cell can’t capture.
“Photons of different energies kick electrons up by different amounts,” said University of Texas Professor Brian Korgel. “Some photons come in with more energy than the cell is optimized to handle, and so a lot of that energy is lost as heat.”
Because of this limitation, scientists had originally believed that simple solar cells would never be able to convert more than about 34 percent of incoming solar radiation to electricity. However, about a decade ago, researchers saw the potential for a single high-energy photon to stimulate multiple “excitons” (pairs of an electron and a positively-charged partner called a “hole”) instead of just one. “This was a very exciting discovery, but we were still skeptical that we could get the electrons out of the material,” Korgel said. . . .