Twisting molecule wrings more power from solar cells

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. …read more