The theoretical limits of solar cell efficiency seem to keep increasing.

I discovered a perfect crystalline structure. That is a very rare sight. While being a perfect crystalline structure we could see that it also absorbed all light. It could become the perfect solar cell, says Martin Aagesen. The discovery of the new material has sparked a lot of attention internationally and has led to an article in Nature Nanotechnology.

I've read fictional stories about conflicts between groups about "light stealing". Buildings that are powered by solar cells in building exterior surfaces are vulnerable to being shaded by new construction. Such buildings were also unpleasant if not dangerous to be around since they sucked both heat and light from the environment to an extent that people outside found distressing.

What does "absorbed all light" really mean? I suppose they'd be dead black. It would seem that dust, dirt and other things would mar the perfection and decrease efficiency. Maybe they would be best used in space. hmmm, I'm getting carried away with speculation here.

Update: Better Batteries Too

The new version, developed through research led by Yi Cui, assistant professor of materials science and engineering, produces 10 times the amount of electricity of existing lithium-ion, known as Li-ion, batteries. . .

The greatly expanded storage capacity could make Li-ion batteries attractive to electric car manufacturers. Cui suggested that they could also be used in homes or offices to store electricity generated by rooftop solar panels. . .

Research on silicon in batteries began three decades ago. Chan explained: "The people kind of gave up on it because the capacity wasn't high enough and the cycle life wasn't good enough. And it was just because of the shape they were using. It was just too big, and they couldn't undergo the volume changes."

Then, along came silicon nanowires. "We just kind of put them together," Chan said.

There are recent developments in using carbon rather than silicon for chips. Carbon is faster but has been a problem to manufacture. New techniques get around the problems. But for these new batteries silicon is replacing carbon for anodes because it has higher capacity. In both cases the relative merits have long been known but couldn't be exploited due to manufacturing challenges.