Quantum-Dot Leap
Tapping tiny crystals' inexplicable light-harvesting talent
One frustration of solar energy is that although it's free, clean, and inexhaustible, it's a major challenge to harvest efficiently. Consider what happens when photons of sunlight hit a solar cell: They strike electrons in semiconductor material and send them on their way as an electric current. Although many solar photons carry enough energy to theoretically unleash several electrons, they almost never free more than one.