New Material for Solar Cells Gleans More Energy From the Sun

Spanish researchers say they have developed a new solar-cell material that absorbs significantly more of the sun’s energy and would dramatically increase efficiency. Traditional silicon-based solar cells, using the energy only from visible light, absorb about 40 percent of solar energy in theory but only 30 percent in practice. The new material uses the energy from infrared photons as well, yielding a theoretical maximum efficiency of 63 percent. Blending titanium and vanadium into the silicon produces a “stepping-stone” effect: Instead of letting infrared photons go by, it stores them until another photon hits and bumps up their energy level, producing power. The researchers say their new cell improves upon previous stepping-stone materials, resulting in the highest theoretical efficiency so far.