Twisting molecule wrings more power from solar cells
(PHYSorg.com Technology)

Inside a solar cell, sunlight excites electrons. But these electrons often don`t last long enough to go on to power cell phones or warm homes. In a promising new type of solar cell, the solar-excited electrons have better odds going on to work. Why? Scientists revealed the dominant force behind the higher efficiency of these promising hybrid organic-inorganic perovskite solar cells. They found that positively charged molecules rotate in the cell. In moving, the molecules screen the excited charge carriers-electrons and holes (missing electrons)-from annihilation. How far the molecules can rotate determines how long the excited electrons and holes last.