Solar Breakthrough Could Provide Power Without Solar Cells 223
An anonymous reader tips a University of Michigan news release about the creation of what's being called an "optical battery" that could lead to the use of solar power without traditional solar cells (abstract). Quoting:
"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.'"
Re:I've been reading about solar breakthroughs (Score:5, Interesting)
It's awesome that they are (apparently) directly generating electricity. Much better than the quaint method of boiling water to turn turbines.
Don't hold your breath. (Score:5, Interesting)
I'm really surprised that the article didn't mention "5 years" as a time scale for when this will be viable, since that's the typical duration mentioned in these sort of articles --- far enough in the future that most will have forgotten about it by the time we get there, but near enough to still feel like it's worth anticipating (in other words, the perfect length of time for a project that needs funding to continue, but may never actually produce desired results).
Re:Beyond the theoretical limit (Score:2, Interesting)
You're right that the concentration factor is about 100 million times (from ~1000W/m^2 sunlight at the Earth's surface), which is crazy high, but I wasn't aware there was a theoretical concentration limit. Where did you get that from and what's the rationale for it?
Satellites not shipping products ... (Score:5, Interesting)
However I would not keep an eye to the shipping products to judge feasibility, I would keep an eye on satellites. Break throughs like the one in this story might first appear in the environment of much higher solar intensity found in space.
Re:Beyond the theoretical limit (Score:5, Interesting)
There's a theorem in imaging that says you cannot focus a light source to create a beam any more intense then at the surface of what is emitting the light. A consequence of this is that you cannot heat something to hotter than the surface temperature of the sun by concentrating sunlight in any way, even if you had a lens the size of the solar system. The spot size that you get will just keep getting bigger.
Incidentally if you were able to do this it would violate the 2nd law of thermodynamics, because you would be moving energy from a cooler object to a warmer one without doing any work, thus decreasing the total entropy of the universe.