Scientists from the University of Michigan have found a new way to capture solar energy without using solar panels and inadvertently discovered a new law of physical motion that has been overlooked for 100 years in the process.
By harnessing a “dramatic and surprising” magnetic effect of light, the research team, led by Professor Stephen Rand from UM’s Department of Applied Physics, say they could produce solar power without using expensive semiconductor-based solar cells.
Although light, like all physical forces, has electric and magnetic effects, until now it was thought the magnetic properties to be too weak to be utilised in any useful way. But when Rand and his team focused light through a non-conductive material, they found the isolated magnetic properties were enhanced by up 100 million times the amount previously expected.
Under these circumstances, the usually negligible magnetic effects of light develop strength equivalent to a strong electric effect. Professor Rand was stunned.
“You could stare at the equations of motion all day and you will not see this possibility,” he said. “It’s a very odd interaction. That’s why it’s been overlooked for more than 100 years.”
The team used glass and lasers to shine intense light and separate the magnetic current, creating an “optical battery.”
When a solar panel is exposed to the sun’s rays, electron activity is generated and capture fine finger-like electrical contacts distributed across the panel. This is then routed through the junction box on the back of the panel and emerges as electricity. Rand says the new process does not absorb light; instead, intense light energy is used to create huge quantities of magnetic force, which can be converted to electricity.
The UM researchers hope to create a new generation of solar harvesting hardware without semiconductors, which are needed to produce charge separation from solar energy in conventional solar panels. They say the new technique could make solar power cheaper, and predict a light-to-energy efficiency rate of 10 percent, which is under polycrystalline and monocrystalline panels, but on par with some thin film solar panels.
“To manufacture modern solar cells, you have to do extensive semiconductor processing,” team member William Fisher says. “All we would need are lenses to focus the light and a fibre to guide it. Glass works for both. It’s already made in bulk, and it doesn’t require as much processing.”
Source : University of Michigan
