Solar power is enjoying a surge of interest lately, due to the nuclear crisis in Japan, rising gas prices and concerns over global climate change. Yet, the cost of solar still deters some people from converting from grid-based electricity.
What if it was possible to generate solar energy without solar cells? In other words, could we harness the power of the sun for our use without having to pay for bulky PV solar panels? According to a recent Forbes Blog post by Alex Knapp, solar technology could take a big step forward relying on breakthrough research at the University of Michigan. Using magnetic properties of light at just the right intensity, Professor Stephen Rand and his associate, William Fisher, have discovered electrical voltage can be generated without needing solar cells.
Light has electric and magnetic components. Until now, scientists thought the effects of the magnetic field were so weak that they could be ignored. What Rand and his colleagues found is that at the right intensity, when light is traveling through a material that does not conduct electricity, the light field can generate magnetic effects that are 100 million times stronger than previously expected. Under these circumstances, the magnetic effects develop 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,” Rand said. “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.”
What makes this possible is a previously undetected brand of “optical rectification,” says William Fisher, a doctoral student in applied physics. 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 sets up a voltage, similar to that in a battery. This electric effect had previously been detected only in crystalline materials that possessed a certain symmetry.
What this all means is that one day we may not need expensive semiconductors to capture solar energy. Instead, solar manufacturers could simply use ubiquitous, cheap materials like glass or transparent ceramics.
This solar technology is still in the conceptual stage, and may take years before it can be reliably used for everyday applications. But perhaps the promise of cheaper solar power is worth the wait.