The inventor of a low-cost solar cell that could be used to build electricity generating windows has been awarded this year's Millennium Technology Prize. Professor Michael Gratzel of the Lausanne Federal Technology Institute received the €800,000 (£660,000) prize at a ceremony in Helsinki.

Professor Gratzel's innovation mimics the way plants turn light into energy. Two British inventors also won prizes of €150,000 (£124,000) each.

..... Explaining his inspiration, he said: "I was always intrigued by the way plants capture sunlight and turn it into fuels like sugar. "Natural photosynthesis was the inspiration, and our solar cell is the only one that mimics the natural photosynthetic process."

Gratzel cells rely on nanotechnology to produce power from sunlight. "We are using nanocrystal films in which the particles are so small, they don't scatter light," said Professor Gratzel.

"You can imagine using those cells as electricity producing windows. "What's very exciting is that you collect light from all sides, so can capture electricity from the inside as well as the outside. "You could think that the glass of all high-rises in New York would be electricity generating panels," he said.

Gratzel cells have recently been launched in consumer products, including as battery charging backpacks, and Professor Gratzel said that the €800,000 prize would benefit his research and go back into science.