Invisible Solar Nano Cells Promise Clean Energy

An anonymous reader writes "ZDNet is reporting that Harvard scientists have developed a silicon nanowire 200 hundred times thinner than a human hair that crank out up to 200 picowatts. Charles Leiber from Harvard University, who devised the technology with colleagues, is quoted: "An individual nanoelectronic device will indeed consume very little power, but to do something interesting will require many interconnected devices and thus the power requirement — even for nanosystems — can be a challenge". Conventional sources, he added, are "bulky, non-renewable and expensive" by comparison."

Comments

a side product of balding hair research

[rgaginol]

what's sad is that this was discovered in the attempt to create a more life like toupe;P

An obvious question?

[Linker3000]

"...Charles Leiber and colleagues at Harvard University, have devised a 'silicon nanowire' that can convert light into electrical energy.... ...Two hundred billionths of a watt may not seem much, but at nanoscale it is enough to provide a steady output of electricity to run ultralow power electronics, including some that could be worn on -- or even inside -- the body. "

Erm, how bright is the inside of a body!?

I Hate Science Reporting

[MBCook]

Virtually invisible to the naked eye, a single strand can crank out up to 200 picowatts.

I hate science reporting. It's also nice to know the editors aren't doing their jobs (ZDNet, I don't blame /.). What is a single strand? Is that 10mm long? 10cm? 1m? There is a big difference between those three. The summary just chops that sentence up worse. And why do they always use human hair as a comparison? Who's hair is that? Some people have very thin hair. For some people it is quite a bit thicker. If you are comparing it to the average, you should include that word. Also are we talking theoretical maximum or a practical estimation under normal daylight conditions?

It's great to know this generates 200 picowatts per something. How about comparing it to a normal production solar cell. I'm glad you can make it thin, but it must need some kind of support structure to survive, so how much thicker does it need to be so it is actually useful? After all, the silicon part of a solar cell is just a fraction of it's thickness.

Re:I Hate Science Reporting

[Falstius]

As someone who teaches MEMs technology, I find myself frequently using the human hair comparison with new students. It is the closet thing to a microstructure that people have daily physical experience with, and helps give a feeling of scale. A 200 micron wide bridge is an abstract number until you understand it is about 1 to 4 hair-widths (depending on whose hair). Its not nearly as meaningless of a unit as LOCs (Libraries of Congress). If you have a better suggestion for a comparison, I'd love to hear it.

Your point about leaving off the length is a good one. Science journalists don't seem to understand enough about what they're covering to know which points are important or which claims are plausible.

Re:I Hate Science Reporting

[fractoid]

The article also contains this gem:

Incoming light generates electrons in the outer shell, which are then swept into the second layer and the inner core along micropores. Nice to see that they're actually generating electrons instead of just moving them around like most of those lazy-ass photovoltaics. I hope they generate positrons at the same time to balance out the overall charge of the universe...

I wonder

[Dr. Eggman]

Any biologists out there who wishes to inform me of how this solar cell compares in efficiency and equivalent energy production for photosynthesis. I understand that they're are two very different forms of energy (storage medium may be a better comparison) but I would be interested as I have thought that perhaps natural evolution had already long ago derived the most efficient ways of recovering energy to drive its organisms. I wonder if the real future of small scale generators/batteries lies with organic synthesis of energy through genetically modified organism with some medium transforming the resulting chemical energy into electrical energy (not unlike a battery but with it's own complications necessary for dealing in the organic compounds) rather than straight up developing life-facsimiles.

Then again maybe I'm just rambling on after approaching the 40th consecutive waking hour... It'd be nice to know.

Re:I wonder

[StikyPad]

I have thought that perhaps natural evolution had already long ago derived the most efficient ways of recovering energy to drive its organisms.

Not usually true. Plants and animals have plenty of other concerns, such as the efficient storage thereof, combating predators, reproducing, etc., any one of which could take precedence over obtaining energy. Is fat the most economical storage medium? It's pretty good, but other factors come into play: it's not toxic to the body, it's pliable, which permits relatively free movement, it's a good insulator, and it provides protection to bones and internal organs (any of which may or may not be an evolutionary side effect). Natural selection is about favoring the most competitive in a particular environment, and obtaining the most energy, while ignoring other factors, is not always the best strategy. A design that extracts more energy from sunlight than pine needles might be more prone to wind damage, pests, molds, fungus, etc. Even if an organism is more efficient at extracting energy than its competitors, that's no guarantee that its the *most* efficient possible design, just that it was good enough.

Additionally, what we're primarily concerned with is electromagnetic energy. There are always losses in any conversion, and if we convert the sunlight into chemical energy, then back into electromagnetic energy, we're guaranteeing more losses than if we can harness/store the sunlight directly. That's why it's often more efficient to use net metering rather than off-grid battery storage alone. Many people opt to include batteries in their solar systems, but that's typically for the purpose of grid independence and/or backup power. Of course there are losses inherent in converting DC to AC, so that must be considered as well. Overall, the more directly you can transfer the power from the source to the load, the more efficient that transition will be.

I'm not a biologist, but I did stay at a Holiday Inn last night.

Hey....

[DoofusOfDeath]

"Invisible" "Solar" "Nano" "Cells" ... "Clean Energy"

I WON SLASHDOT BINGO!!!