Solar Power Without Solar Cells: University of Michigan Researchers Discovered Way To Make “Optical Battery”

By on Apr 15, 2011 in Science, Technology, United States, World Comments

University of Michigan researchers were reported to have found a way to produce solar power without using the traditional semiconductor-based solar cells, several science news sites reported on Wednesday.

According to Stephen Rand, a professor in the departments of Electrical Engineering and Computer Science, Physics and Applied Physics, the researchers discovered a way to make an “optical battery.”

Solar Panels
Solar Panels
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Rand and his colleagues found out that at the right intensity, what was thought to be a very weak magnetic field of light by scientists for many years, can generate magnetic effects that are 100 million times stronger than previously expected. These magnetic effects were said to have a strength equivalent to a strong electric effect.

“This could lead to a new kind of solar cell without semiconductors and without absorption to produce charge separation. In solar cells, the light goes into a material, gets absorbed and creates heat. Here, we expect to have a very low heat load. Instead of the light being absorbed, energy is stored in the magnetic moment. Intense magnetization can be induced by intense light and then it is ultimately capable of providing a capacitive power source,” Rand was quoted saying.

William Fisher, a doctoral student in applied physics said that this is possible due to a previously undetected brand of “optical rectification.” Optical rectification was said to be only detected in crystalline materials that have a certain symmetry. However, Rand and Fisher found that under the right circumstances and in other types of materials, the light’s magnetic field can also create optical rectification.

In this new technique, instead of using semiconductor, the light will be shone through a material that does not conduct electricity, such as glass. Light must be focused to an intensity of 10 million watts per square centimeter. Although sunlight is not this intense, Fisher said that new materials are being sought that would work with lower intensities.

The researchers said that this new technique could make a cheaper solar power. “To manufacture modern solar cells, you have to do extensive semiconductor processing. All we would need are lenses to focus the light and a fiber to guide it. Glass works for both. It’s already made in bulk, and it doesn’t require as much processing. Transparent ceramics might be even better,” Fisher explained.

This summer, the researchers will experiment on harnessing this power with laser light, and then with sunlight.

Their paper is titled “Optically-induced charge separation and terahertz emission in unbiased dielectrics.” University of Michigan was said to be pursuing patent protection for the intellectual property.

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