When UCLA researcher Yang Yang looks out a window, he sees opportunity. Yang's focus isn't on what's beyond the window, but the window itself -- particularly its potential for energy production. Yang is a professor of materials science and engineering, and his team recently created a photovoltaic plastic that is more than 70% transparent to the human eye. Though the idea of a transparent solar collector seems almost counter-productive, the secret is transparency to only certain wavelengths. In this case, Yang's photovoltaic plastics are almost entirely transparent in the visible spectrum, but capture plenty of energy from infrared and other frequencies. "These results open the potential for visibly transparent polymer solar cells as add-on components of portable electronics, smart windows and building-integrated photovoltaics and in other applications," Yang said.