Scientists at Michigan State University announced this week the creation of a transparent luminescent solar concentrator" that could turn windows and even cellphone screens into solar-power generators. The material works by absorbing light in the invisible spectrum (ultraviolet and near infrared) and then re-emitting it in the infrared. The infrared light is then channeled to the edge of the clear surface, where thin strips of photovoltaic cells generate the power. Because we cannot see infrared or ultraviolet light, the material remains transparent even while concentrating sunlight. Previous luminescent solar concentrators have been developed, but they emitted light in the visible spectrum, creating a stained-glass effect. "No one wants to sit behind colored glass," Richard Lunt, who leads the lab researching this new technology, said. The new technology is promising, but needs to be made more efficient. Researchers say that the solar conversion efficiency is around one percent. Ideally, this could be increased to more than five percent. Luminescent solar concentrators are less efficient than traditional photovoltaics, which absorb a larger range of wavelengths, but they could allow energy harvesting on surfaces that would otherwise never be used to generate power. The transparent technology could be used in a variety of applications, Lunt said, and its affordability means it has the potential for eventual commercial or industrial use. "Ultimately we want to make solar harvesting surfaces that you do not even know are there," he said. The researchers' findings were published in the journal Advanced Optical Materials in July.