In 1991, a pair of scientists published a paper in Nature, detailing a intriguing new discovery: the dye-sensitized solar cell. Today, one of them won €800,000 for his efforts, and the 2010 Millennium Technology Prize. Michael Grätzel accepted the award for the low-cost solar cells that often bear his name, and which make possible the sunglasses, windows and iPhone patents we seem to spot every few days. Hear the good professor speak about his invention in a video after the break.