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MIT Professor Daniel Nocera claims to have invented the first affordable solar cell capable of mimicking nature and performing photosynthesis -- splitting water.  (Source: Christopher Harting/MIT)

Another study examined how quantum dots may be able to perform "Multiple Exciton Generation" an unusual phenomena that sees an excited quantum dot electron (blue, left) transfer energy to multiple electrons in another quantum dot (green, right)  (Source: Mark T. Lusk, Department of Physics, Colorado School of Mines)
"Her green plastic watering can/For her fake Chinese (silicon) plant/In the fake (silicon) earth."

One of the most promising sources of future energy is solar power.  We're currently only harvesting a minuscule fraction of the estimated 12.2 billion kilowatt-hours of solar energy that hits the Earth every day [source].  While nuclear fission and fusion power also will be critical to the future of man, solar power may be usable on planetoids that lack fissile fuels like uranium and fussile fuels like deuterium.

Before we can get to such ambitious terrestrial or interplanetary objectives, much work needs to be done.  A pair of new studies published by the Massachusetts Institute of Technology and the Colorado School of Mines offer intriguing tools that could one day be applied to making solar power more efficient.

I. Growing a Solar "Tree"

Scientists often find that nature has produced designs that rival any that mankind has cooked up.  A perfect example of that is the tree.  

A dominant plant species across much of the world, trees have solved much of the problems that have puzzled alternative energy scientists.  They not only store collected solar energy in polysaccharides, but also manage an immensely large solar collecting surface via their multipurpose evolutionary invention, the leaf.

Using the chemical model of the leaf, researchers at MIT created a poker card-sized silicon cell, doped with special catalysts and controlling electronics.  The team reports that the device is capable of producing an abundantly positive energy balance by splitting water into hydrogen and oxygen.  The reactions it carries out are similar to those that occur inside chloroplasts in photosynthetic plant cells.

The emitted gases could be harvested and stored for use powering a fuel cell.  Daniel Nocera, Ph.D. [profile], who led the team, describes [press release], "A practical artificial leaf has been one of the Holy Grails of science for decades. We believe we have done it. The artificial leaf shows particular promise as an inexpensive source of electricity for homes of the poor in developing countries. Our goal is to make each home its own power station.  One can envision villages in India and Africa not long from now purchasing an affordable basic power system based on this technology."

Professor Nocera reports that his leaf actually beats nature's design in efficiency by a factor of 10, and may be even more efficient in the future.  Of course it lacks natural leafy plants' ability to heal from damage, self-replicate, and self-generate from ground resources.  Nonetheless, the efficiency mark is an impressive achievement.

The key to that success is special nickel-cobalt catalyst that Professor Nocera cooked up.  Much like photosynthetic pigments that use metal ions as their active center, these catalysts use the harvest solar energy to perform chemical reactions.

John Turner of the U.S. National Renewable Energy Laboratory in Boulder, Colorado created a similar "solar leaf" a decade ago, but it relied on expensive rare metal catalysts.  Since then, many other researchers have created new solar leaf designs, but most of their designs remained quite expensive or lacked efficiency.

By contrast Professor Nocera's design is far cheaper, while maintaining a respectable efficiency.

The key obstacle now to this technology being practically suited for mass production is the lack of availability of cheap, durable fuel cells.  Currently fuel cells capable of producing enough energy to power a modern house remain quite expensive, costing tens, if not hundreds of thousands of dollars.  Still, it is reasonable to hope that similar breakthroughs will one day be able to drop the cost of fuel cells enough that the entire system will become feasible for mass deployment.

MIT's research was funded by The National Science Foundation (NSF) and the Chesonis Family Foundation.  It was presented at the 241st National Meeting of the American Chemical Society(ACS).

II. Connecting the Quantum Dots

Quantum dots are outlandish human-constructed atoms that confine electrons to a three dimensional space in a crystal-like motif.  The electrons are capable of absorbing photons to form excitons and the properties of quantum dots themselves are somewhat like bulk semiconductors, making them an attractive target for photodetectors or solar cells.

Scientists are still struggling to understand the complex structures they've created, though.  The dots operate on quantum physics rules far different from those observed on a macroscopic scale.

New research at the Colorado School of Mines offers evidence in support of a controversial theory called multiple exciton generation (MEG), which suggests that a quantum dot's electron that has absorbed light energy from a single photon can transfer that energy to multiple other electrons.

Previous studies have been remarkably inconsistent on the possible relationship between quantum dot size and MEG events, thus it was an attractive target for simulation, says the research team.  

Using a computer cluster funded by a NSF grant the team revealed that each size of quantum dot is capable of performing MEG for a select slice of the solar spectrum.  Smaller dots have the highest efficiency of electricity generation from their spectrum-dependent MEG events.

The team's leader, Professor Mark Lusk [profile], says that the results indicate that using a mix of quantum dots could produce superior electricity generation capabilities in future solar cells.  He states [press release], "We can now design nanostructured materials that generate more than one exciton from a single photon of light, putting to good use a large portion of the energy that would otherwise just heat up a solar cell."

The results were published in a paper [abstract] in the peer-reviewed journal ACS Nano.



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what's the catch?
By superPC on 3/29/2011 9:37:31 AM , Rating: 3
come on there's got to be a catch here. this is too good to be true. use some special materials plus sunlight and water and presto instant hydrogen? how about those catalyst? won't they degrade and need replacement? or the structure on the silicone? don't they require replacement? i have to admit the youtube video ( http://www.youtube.com/watch?v=4-M9VU_36NQ&feature... ) looks really promising.

and fuel cell? why use expensive fuel cell when you can create hydrogen out of water efficiently? just burn the gas in generators or ICE.




RE: what's the catch?
By mtcoder on 3/29/2011 10:21:52 AM , Rating: 2
Problem is just that burning generates heat, which has to be dealt with, not to mention you lose a ton of energy due to the heat lose if you don't capture and utilize the heat. That is where fuel cells start to come into play, they do the conversion much more effectively. Also don't worry there are a few new fuel cells that are in works for home use. They utilize the heat waste to heat house hold water tanks, and to power radiator style heat systems, when its cold. They also use it to create excess steam for self contained generators. So fuel cells are starting to come way down in cost, way up in safety, and very much so in efficiency.

The leaf would probably last a very long time actually if blocked from harmful elements. I would envision them similar to solar panels, they do the same function basically just at a level / system a kin to nature, using low cost materials.
Granted not as low cost as nature has managed, but still lower costs. Think about a house "plant" that set in a snow globe like bubble in the window that generated enough power to run your TV. Put a few in each room and you start to reduce your power costs greatly.

Now do I see them being made into plant shaped items? not really, though who knows. LOL I do see them though as improved solar cells.


RE: what's the catch?
By AnnihilatorX on 3/29/2011 1:04:13 PM , Rating: 3
Fuel cells can be scaled both up and down, ICE can't.
Small scale solar power generation is what we need. Localised power generation is much more attractive prospect than centralised solar farms.

Catalysts are, in essence, called catalyst because they are not consumed nor degrade, within operation life of a product. If you are using a material which degrades quickily, it's not fit for purpose to be called a catalyst. In application like this, facilating electrons transfer of energy, is not so energy intensive, I don't see how it will be a problem to the integrity any catalyst material.


RE: what's the catch?
By BruceLeet on 3/29/2011 3:03:27 PM , Rating: 3
Patents, its always the catch.


RE: what's the catch?
By Solandri on 3/29/2011 5:11:28 PM , Rating: 2
The catch is that right now only about 5.5% of the energy in the sunlight is diverted into generating hydrogen. To give you an idea how low that is, photosynthesis in sugar cane is about 7%-8% efficient.
http://en.wikipedia.org/wiki/Photosynthetic_effici...

The end product is of course sugar and cellulose (sugar molecules linked together) instead of hydrogen gas. But sugar is a helluva lot more compact and a more transportable energy storage medium than gaseous hydrogen. You can even ferment it to convert it into alcohols, which you can then use as a liquid fuel. That's what biofuels are. The best part is - it costs nothing to build. Plants and algae are self-constructing and self-replicating.

This will be a good invention if they can get the efficiency up above maybe 20%. But as it stands right now, it's inferior to biofuels and burning wood.


RE: what's the catch?
By rs2 on 3/29/2011 11:21:51 PM , Rating: 4
quote:
The best part is - it costs nothing to build. Plants and algae are self-constructing and self-replicating.


Self-constructing so long as the required raw materials are available from the environment in sufficient quantities for the plant to replicate and grow. For large scale operations the cost of replenishing these raw materials (typically in the form of fertilizer), while generally manageable, is certainly not "nothing".

Still I like the idea of using nature to produce the things we need. But plants aren't some magic entity that create themselves out of nothing but light and air as you made it sound.


long, thin solar cell
By zozzlhandler on 3/29/2011 11:08:11 AM , Rating: 2
...researchers at MIT created a poker-sized silicon cell, doped ...

Did you mean "poker chip sized"?




RE: long, thin solar cell
By erple2 on 3/29/2011 11:21:52 AM , Rating: 1
Huh. I interpreted this as the common, household variety instead: http://en.wikipedia.org/wiki/File:Fireplace_poker....


RE: long, thin solar cell
By zozzlhandler on 3/29/2011 12:29:59 PM , Rating: 2
Thats what I meant by a long, thin solar cell...


It's (almost) all solar power
By Schrag4 on 3/29/2011 1:49:10 PM , Rating: 2
quote:
One of the most promising sources of future energy is solar power.


I know it's a bit of a stretch (not much really), but fossil fuels, ethynol, biodiesel, hydroelectric, and wind are all solar power.




By ClownPuncher on 3/29/2011 2:13:14 PM , Rating: 2
Inderect vs. direct. I'm glad you made that connection, though. Cookie?


By Flunk on 3/29/2011 10:18:47 AM , Rating: 3
Your comment belies a lack of understanding for the subject matter. Leaves evolved over millions of years, each change improving efficiency (or alternately not and making that line of plants extinct).

It taking one man a few years to emulate something that took millions of years to develop naturally isn't strange or unusual in the least.


By gaborb on 3/29/2011 11:02:14 AM , Rating: 3
Well said Flunk. What pains me is when people lack basic understand of how the world works around them and then read scientific articles.

We have tons and tons of evidence that stuff has been around for Billions (not millions) of years changing and evolving.

If the world is not as old as scientists belive, someone took a freaking lot of effort making it look like it did.

How to turn a scientific breakthrough article into an unnecessary discussion.


By on1wl on 3/29/2011 1:14:19 PM , Rating: 3
"Evolution has never been observed"? Wrong. It is not only observed by 1000's of micro-biology students every year, the process is used in molecular genetics labs every day for creation of anti-biotic resistance populations of bacteria for gene research. We can argue whether or not God invented evolution, (and gravity for that matter), but the existence of evolution is clear. 99% of all species that have ever existed were extinct before man learned how to make a wheel. Evolution tries everything, and most of the time it fails. Fortunately it forgets failure and remembers success.


By Arsynic on 3/29/2011 2:16:01 PM , Rating: 1
No, that's the revised definition of evolution that I was talking about...


By Whedonic on 3/30/2011 5:11:34 AM , Rating: 2
I'm terribly curious: why do you say that's a revised definition? That's the basic shape of evolution that I've always heard.

ALSO - There's nothing wrong with revising scientific theories and ideas. That's what science does.


By saganhill on 3/29/2011 3:11:22 PM , Rating: 2
No,no you have that reversed. Your so-called reasoning is credulity at its best. Fluke had it correct the first time. Getting your information from the bible is not science.


By notfeelingit on 3/29/2011 3:40:33 PM , Rating: 3
Huh? Evolution is readily observed in the present. As in right now. It's the reason antibiotics require a prescription to be purchased.

Were YOU there to observe the supposed jesus christ? What, are you going to tell me that some authority figure 'told you so' and thus you are going to believe it to be true?


By gixser on 3/29/2011 4:08:51 PM , Rating: 2
quote:
and ask God the questions that are on your mind and he will answer you and make you a free man, a man free from the darkness of ignorance from the chains of lies that daily torment you.


....and thus God create science. Do thy Lords bidding!


By themaster08 on 3/29/2011 4:17:03 PM , Rating: 2
quote:
the darkness of ignorance from the chains of lies that daily torment you.
There was me thinking that was religion's job for the past 5000 years. Thank you for reassuring me that I won't be straight jacketed for talking to myself.


By themaster08 on 3/29/2011 5:39:20 PM , Rating: 2
You can't go on believing that there is a God because YOU says there is a God.. it's like saying that unicorns exist because you says so.

It works both ways, my preaching friend.


By notfeelingit on 3/29/2011 5:40:12 PM , Rating: 4
Antibiotics turn into a frog? There's no way you can be serious about that statement. The reason antibiotics are controlled by prescription is to prevent their overuse and in turn the rapid *mutation* of bacteria into more resistant strains. We can observe evolution of bacteria in real time. You can witness it with your own eyes, and all you need is a microscope and some cultures.
http://www.bacteriamuseum.org/cms/Evolution/evolut...

Countless eye witnesses of jesus? False. The bible is a poorly translated selection (only the "canonized" documents made the cut) of ancient texts transcribed based on stories passed down from illiterate wandering shepherds. To use your own court of law analogy, that chain of custody would completely forfeit the document as evidence.


By Cheesew1z69 on 3/30/2011 9:04:02 AM , Rating: 1
Evolution is all around you...man some of you people are just...insane...


By erple2 on 3/29/2011 11:07:57 AM , Rating: 2
If you subscribe to the notion that the universe is only about 5000 or so years old, then I can see your point.

If you instead subscribe to the notion that life on earth is billions of years old (about 3.8 billion), then it seems reasonable to me that in about 800 to 1500 million years, photosynthesis may have started working, albeit in a primitive form. Give yourself another 2.7 to 3 billion years, and maybe it is reasonable that trees and other plants have managed to improve on photosynthesis to where they are today.


By erple2 on 3/29/2011 11:20:02 AM , Rating: 2
I was slightly mistaken - plants started appearing on land around 400-500 million years ago. So while photosynthesis may have occurred billions of years ago (about 2.7 billion), land-dwelling plants didn't really start to show up until 400-500 million years. Even then, the "modern" plant that we all know and love today, with features like roots and leaves, looks to have started appearing around 370-380 million years ago ("Middle of the Devonian period").

Note, all of this is from wikipedia, so if you don't trust that source, go to their primary sources instead to research for yourself.


By mmcdonalataocdotgov on 3/29/2011 1:11:26 PM , Rating: 4
People have become gullible and have started to assume many things nowadays. To believe in creationism without any proof for it is utter foolishness. There is absolutely no proof of creation so why bother believing such a theory and state your entire life on it and possibly beyond? Nobody never ever have observed creation so.. yes.. creation is a myth. While I have personally been talking to my biology professor every day experiencing him being real the people who believe in creation are grasping for straws in order to justify their reactionary lifestyles of an arse. If you throw up into the air nothing you don't expect to receive something and yet that is exactly what the theory of creation is trying to tell you--if you start with nothing then over 7 days there is going to be something and that something will be a computer?.. that's not how things work in this world. Where there is a design there is a designer, where there is an entropic system, order arises. There is a Darwin.


By Arsynic on 3/29/2011 2:17:51 PM , Rating: 2
Belief in Intelligent Design != creationism.


By mmcdonalataocdotgov on 3/29/2011 2:30:05 PM , Rating: 2
That's the quasi-scientific end run to decouple it from its rational constructionist misinterpreted book of genesis origin, and to remove the stigma of religious dogma.


By mfergus on 3/29/2011 3:10:23 PM , Rating: 2
Why is religion constantly brought up here by some people? This isn't a religious website.


By themaster08 on 3/29/2011 4:05:03 PM , Rating: 2
quote:
When all people come to the knowledge of the Truth that you don't get something out of nothing
Does that also apply to God himself?


By themaster08 on 3/29/2011 5:40:54 PM , Rating: 2
How can you know that if there is no evidence?


By mfergus on 3/29/2011 6:14:43 PM , Rating: 2
Im sure you wouldn't like athiests trolling religious forums so I don't see why you would troll dailytech.


By themaster08 on 3/29/2011 6:17:28 PM , Rating: 2
Because science is religion's worst enemy.


By mfergus on 3/29/2011 6:19:18 PM , Rating: 2
Even if his reasons are noble he should know hes only gonna fall on deaf ears on a science website. There's no scientific evidence of a god. There's no proof there's not a god either but that doesnt prove god exists.


By themaster08 on 3/29/2011 6:23:13 PM , Rating: 2
Hence the reason religion is a belief and nothing more.


By hawwah on 3/29/2011 10:15:45 PM , Rating: 2
The sad thing about people is they can never separate their own personal issues, their prejudices, and own world view and actually do objectionable science.
Darwin was a racist, his own writings are littered with his views on white European superiority. The introduction of his 'evolution' theology into society led directly to a increase in racism by orders of magnitude, and directly brought about the most atrocious acts of the last century including eugenics and the Holocaust.
As part of a persons world view, Darwin's teachings are entirely destructive, introducing a zero level of morality, where the only rule is kill or be killed. Serial killers, rapists, genocidal dictators, as far as evolution goes are the cats meow, the best of the best. In terms of eugenics and the holocaust, doctors, nurses, politicians, scientists and of course an entire society, believed as many still evolutionists still do, that they themselves were and are 'superior' or more 'evolved' than others. Richard Dawkins is a great example of this, because of course anyone who doesn't believe in evolution is obviously a 'idiot' or 'moron'. Just as everyone who was massacred by the Nazi's, were 'subhuman' and inferior, and of course anyone who disagrees with an evolutionist must be less evolved, otherwise they would be an evolutionist themselves and have complex ‘scientific’ thoughts...
But then of course evolution is entirely scientific, which is of course why we are now being taught that life evolved by piggy backing on crystals, on the planet krypton, and that it was the Kryptonians who ‘seeded’ the earth with life!!


By Paj on 3/30/2011 7:54:02 AM , Rating: 2
Evolutionary theory did not cause the Holocaust or eugenics - xenophobia and social prejudices did. They existed long before evolution, and will exist for some time yet.

Darwin himself did much to dismiss the perceived differences between races at the time, highlighting what they had in common.

Evolution is biology. It is descriptive, not prescriptive - yet it has been blamed for many things, from pre-martial sex to communism. Which makes your comment...

quote:
The sad thing about people is they can never separate their own personal issues, their prejudices, and own world view and actually do objectionable science.


...all the more ironic.


By hawwah on 3/30/2011 8:49:04 PM , Rating: 2
To say that evolution is biology implies that evolution = biology or that evolution = science; when in fact biology can as a science only provide evidence to help prove or disprove a given theory. For evolution to occur there would have to be a natural mechanism, a scientific fact, by which genetic information or DNA could be created. There is no biological mechanism, or mechanism in any field of science which allows this.
As far a eugenics and the holocaust are concerned, as I said, these were events and actions taken by scientists, doctors, nurses and many others; whose belief in evolution gave them cause and justification for those actions. Evolution from its inception, has always been exceedingly adept at introducing egocentric believes into a persons worldview. And of course as part of ones worldview evolution will inherently degrade all concept of morality.
It is extremely difficult for anyone to separate their worldview entirely, as it provides the basis for how we think and understand the world. The core beliefs that make up our worldview will either aid or discourage things like racism or religious racism, as far as they are able. Evolution largely supports and promotes an atheistic belief system, something that people like Richard Dawkins have admitted; prior to the theory no atheist in the world was considered intellectual because they had no basis on which to support their beliefs. Today however evolution is still the only support the atheist religion has to justify their perspective, which is why they defend it so ferociously even without any scientific mechanism. And as a religion, it is the only one, which by its own nature requires the believer to admit all other religions and their beliefs in part or as a whole are wrong and incorrect. Its just to bad that most people have never taken the time to step back from what they believe, ask ‘why do i believe this’, and follow the implications of their beliefs to there logical conclusion. (assuming you can reach that conclusion without having your worldview distort it)


By notfeelingit on 3/30/2011 11:18:13 AM , Rating: 2
Most of what you've stated here is verifiably false. Darwin wasn't a racist.
http://rationalrevolution.net/articles/darwin_nazi...

Evolution does not promote racism. Quite the contrary, diversity is a key component to gene expression, and a species largely benefits from it.

Without a god you have a zero level of morality? I find it disturbing that you would have no problem murdering another individual if you found out tomorrow that there was no god.

Science and morality aren't mutually exclusive, but science and religion are. I might even argue that religion and morality are at odds with one another.
http://www.huffingtonpost.com/sam-harris/a-science...


By EBH on 3/29/2011 2:10:29 PM , Rating: 1
I agree. It is a neat idea but hardly as efficient as nature.
What is the overall footprint caused by the design and implementation?

Humans think they can describe the universe using 5 vowel sounds and noises produced by air pressure.

At best humans can only emualte what they experience with their dulled down sense perceptions.

So what if this was done in lab at a very small scale. It will never replicate what nature does across the entire planet without leaving a huge ass footprint.


Get real!
By JessusChristDoOTcom on 3/29/11, Rating: -1
"It looks like the iPhone 4 might be their Vista, and I'm okay with that." -- Microsoft COO Kevin Turner














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