Solar Power: Possible breakthrough could result in drop in cost
The breakthrough – unveiled Friday in a scientific paper in the Journal of Applied Physics by University of Michigan researchers – shows that if light is intense enough, it can, when traveling through nonconductive material, such as glass, at the right intensity can produce magnetic fields 100 million times stronger than previously deemed possible.
During these conditions, the magnetic field has enough strength to equal a strong electric effect, producing an “optical battery” that leads to “a new kind of solar cell without semiconductors and without absorption to produce charge separation”, Prof. Stephen Rand said. Under these circumstances, the magnetic effects develop strength equivalent to a strong electric effect.
A new kind of solar cell utilising this effect would not require absorption of light to produce energy. Instead, energy can be derived from the intensive magnetisation induced by the light.
To manufacture modern solar cells, extensive semiconductor processing is required. With this new type of generation, all that is required would be lenses to focus the light and a fibre to guide it, both of which can be made efficiently out of glass.
According to the researchers, the core of the discovery is a new type of “optical rectification”. In traditional optical rectification, light’s electric field causes a charge separation, or a pulling apart of the positive and negative charges in a material. This greats a voltage.
This electric effect had previously been detected only in crystalline materials that possessed a certain symmetry, but the researchers found that under the right circumstances and in other types of materials, the light’s magnetic field can also create optical rectification.
In a paper published in the Journal of Applied Physics, Rand exposed the research using a new technique that requires “lenses to focus the light and a fiber to guide it, rather than semiconductor processing.
In terms of making this a practical, low cost power producer there is a challenge in the fact that the intensity of the light must be huge about 10 million watts per square centimeter. Why is that a big deal? Because ordinary sunlight is much less than even one watt per square centimeter.