Dyed plastic doubles solar cell power

MIT Technology Review : Concentrating light before it strikes a solar cell is one of the most effective ways to increase the cell’s efficiency. John Rogers of the University of Illinois at Urbana-Champaign and his colleagues have developed a method for concentrating light that uses a dyed plastic sheet. The dye in the plastic is luminescent, meaning it reemits the light it absorbs. The reemitted light stays in the sheet of plastic and moves through it, much like light travels along fiber-optic cables, until it can be directed onto the solar cell. To further increase the device’s efficiency, the researchers added a material that reflects the wavelengths of light not absorbed by the dye. Thus the concentration of light directed onto the solar cell is increased 10 times and the power generated by the cell is doubled. The team plans to make larger sheets of the plastic and combine them with arrays of small solar cells, so that smaller panels could generate more electricity and larger panels would require less photoelectric material to generate the same amount of electricity. The researchers also hope to combine the dyed plastic with flexible panels to accommodate irregular surfaces.