More power from the sun

Solar energy is now growing faster than any other form of renewable power. One reason is that the cost of manufacturing is 100 times cheaper than 30 years ago. “When I came to France in the early 1980s, only idealists were interested in solar energy,” says Pere Roca, director of the Laboratory of Physics of Interfaces and Thin Films at École Polytechnique in Paris. “But the technology has now become profitable.”

A native of Catalonia, Roca hopes his research will further reduce costs. He has developed a process that requires 100 times less silicon. It is designed to make the thin films of silicon used in producing photovoltaic structures even thinner (a few microns), lighter and more flexible. Additionally, he has discovered a crystalline silicon manufacturing technique, using cold plasmas, that work at 200 °C rather than 1,000 °C, considerably reducing energy use.

Another goal is to increase the efficiency of solar panels from 10%-20% to 50%. The thin-film technology will help. “The solar spectrum is divided into several sections,” Roca explains. “The multi-layer structure of solar cells harnesses a maximum amount of energy.” He believes the technology can be adapted to transparent panels, which could in the future replace window glass in homes.

Pere Roca

Director of the Laboratory of Physics of Interfaces and Thin Films, École Polytechnique Paris