Nano-Antennas for Solar, Lighting, and Climate Control

Written by on February 7, 2008

Last week EcoGeek stumbled across a little story about some little antennas that could, just maybe, revolutionize not just the solar industry, not just the energy industry, but the whole entire world.

Well, we thought there was a bigger story there than we could get from one press release, so we contacted the scientists behind the project and it turned out we were right. Dr. Steven Novack took some time to tell us about his nano-antenna (or has he calls them, nantenna) arrays, and some of their potential applications.

I was blown away.

The original article discussed how nantennas could be used as a solar panel that could beat all current efficiencies at a much lower cost. But it turns out that nanetennas have dozens of other uses, many fascinating for EcoGeeks. These include:

  • Passive, energy-neutral cooling by converting infrared radiation into radiation that we don’t feel as heat (like radio waves)
  • Passive heating by turning radiation we don’t feel as heat into infrared radiation
  • Extremely efficient lighting by basically broadcasting photons from the nantennas. As it’s basically the solar process in reverse (photons from electrons, instead of electrons from photons), this is just as feasible as the solar applications
  • Passive heating or cooling within clothing
  • Electricitiy production in clothing by harnessing our bodies’ radiation.

Dr. Novack was kind enough to answer some of our questions. Keep on reading if you want to hear more about this fascinating technology, and where it’s headed five, ten, and twenty years down the road.

EcoGeek: So tell me about your nano-antenna arrays.

Dr. Steven Novack: All antennas are very good at receiving and transmitting electromagnetic radiation. But the difficulty has been creating nantennas of the proper size to capture the wavelengths emitted by the sun. The ability to tune the antenna to the size of the wavelength is very important.

EG: Can you make these arrays pick up radiation throughout the sun’s spectrum, or is it just one specific wavelength?

SN: We can do both; we’re very good at tuning antennas to one specific frequency and very good at making them broadband.

However, INL is fairly new in this world of nanotechnology. Because of that, we’re working to get a product out that would be easier for us to prototype. So we’ve selected a little bit longer wavelengths. As the technology progresses, we’ll certainly be interested in moving that down to the visible range.

EG: Can you talk a bit about the materials that go into these new panels?

SN: Materials are fairly straightforward. We need some sort of substrate as a base, and we’ve chosen a plastic to keep costs low. We have a pattern that we stamp onto the plastic, and then we deposit certain kinds of metals. The metals have to have certain characteristics. For the research phase, we’re focusing less on cost and more on the amount we know about them. The current prototype is being done with gold. The entire one foot by two foot sheet that we created used less than 60 cents of gold, but if we have to go to aluminum, copper, or silver, we could certainly do that.

EG: Right now there your nantenna array can’t convert the energy it creates into a useful current. I’ve heard that you’ll need another nano-electronic component to make that a possibility. Has there been progress in that area?

SN: A lot of scientists are working on nanoelectronics to support optical computing. There’s been a lot of breakthroughs in the last year or so in terms of prototypes that can handle these types of currents. We have not yet attempted to integrate them into the array, but we’re looking for strategic partners that can help us with that.

EG: So when you talk about mass production, how mass are we talking about?

SN: The manufacturing process is part of what we were recognized for in this year’s Nano50 awards. We’re pretty good at large-scale manufacturing, and we’re hoping for roll-to-roll processing.

EG: Does this excite you more than just scientifically?

SN: This is probably one of the more socially significant projects that we’ve done. Obviously, with the world economy’s need for cheap energy, we’re hopefully going to make life better for everyone.That’s definitely a driving force.

EG: So do you think about the environment as you work on this projects?

SN: When we think about manufacturing, we think about the materials and processes as well as the end result. The environment is a huge factor. We only look at stuff that fits our environmental criteria. There’s no sense in trying to help the environment if the process creates a negative waste stream.

And then there’s an overall concept of heat and entropy, and how much we waste our energy as heat.

Antennas that are good in receiving in an area are also very good at emitting in an area.

EG: So are you saying that these could be a light source as well as a light collector?

SN: There are some challenges to that concept that we’re going to be working on. But with your imagination you can probably think of more applications than I can.

The first application I see is: "Here’s a nice way to cool a room." The solar applications are probably more important, but we’re a lot closer to that kind of passive temperature management.

EG: On that very exciting note, I’ll just ask if you can think of any way to help our world stay sustainable.

SN: My personal hope is that we decrease world conflict by increasing availability of resources so that people can have a better life. There’s a direct correlation there. And, of course, I’d love to see more emphasis put onto funding this type of work.


26 responses to “Nano-Antennas for Solar, Lighting, and Climate Control”

  1. Dmitry Zimnitsky says:

    Today you can not straighten out the high frequencies, but can be given through the active electrical resistance heat, which absorbs nanoantenna. Obtain an analog of the thermoelectric Peltier element, but much cheaper.

  2. Bob21 says:

    These could cool a room
    Carbon Man,

    These actually could cool a room under certain cercumstances. It’s not that mysterious. The reason is that Novack is not talking about getting useful energy at equilibrium from a room but getting energy out when a room deviates from equalibrium. Say your walls are coated with nanoantenna’s at some fixed temperature like 69 F. Say you now have a party and the room temperatures rises. The walls act as a heat sink shunting the excess heat away. No different than if the walls were a large thermal mass at 69 F and the room air temp shot up to 80F, the walls eventually shunt away the excess heat. In fact I think the walls coated with these antenna’s would keep the heat from building up because they wuold be a sink for excess heat in the air. In that sense, they do not *cool* a room as much as keep a room from getting hot. There is a difference.

    So, while I agree with you that technically these antenna’s if at equilibrium with the environment would not work, the practical uses are in situations not in equilibrium.

  3. carbon man says:

    What the second law allows
    Heat engines require a temperature difference. The Carnot limit is a quantitative formula that gives the amount of useful energy that can be extracted from the hot object (the unused energy goes into the cold object). The higher the ratio in absolute temperatures, the higher the efficiency. This law does not apply to “ordered” energy such as coherent microwaves from an antenna or macroscopic mechanical motion. It does apply to (nearly) thermal radiators such the sun, earth, walls, etc. The sun is so hot that 90-95% of energy can be extracted in theory. No useful energy can be extracted from a room at a uniform temperature, just as a glass of water does not spontaneously turn into ice and steam. Any attempt to create a temperature difference (i.e. refrigerating the nantenna) will take more energy than it will generate. However, solarcells and airconditioners are about 1/3 as efficient compared to these thermodynamic limits, and expensive. There is vast room for improvement here. No laws of physics need to be harmed in the making of this revolution!

  4. Steve Hall says:

    The next tricky bit is the rectifier to get down to dc. Only cheap solution looks to be MIM diodes.

    Would be good to see a breakthrough there.

  5. R. Frist says:

    But it clearly would violate the 2nd law.
    The 2nd law says that for ANY process the entropy of the universe must increase. Where is the increase in their hypothetical system? With antennas one can capture some energy from low entropy coherent radiation (microwave, radio, laser, etc.) but not from high entropy black body radiation. This was a futile exercise.

  6. Bob21 says:

    I don’t think this violates the 2Nd law.
    I believe that there is no violation of the 2nd law
    in having an antenna pick up IR. If antenna’s did not work for IR they would not work for cell phones or radio either and the wavelengths in those are far less energetic than IR at 10 microns. Regarding the antenna in the snow, well the earth does emit a huge amount of IR at an almost constant rate which varies slightly over the year and is between 300 to 400 W/m^2 most of the year in the midwest. This is just the release of absorbed solar energy which has to be since the earth is in equilibrium or it heats up like Venus. So, I believe you could pull energy from the re-radiated IR
    and heat your house in the winter just as you can heat your house from the sun during the day. In fact you are just using converted, downshifted re-radiated solar energy. The confusion comes in when one thinks the air temperature has any relation to getting IR energy in the antenna- since it feels cold out at night in the winter how can there possibly be a lot of energy? I think the answer is that the IR waves pass through the air without heating it too much so you don’t notice it. Regarding the reusing the same energy over and over again, that would work for a while as you reused some waste heat but you would eventually run up against the the increase in entropy which would make the energy useless but since the earth, compared to your house, is essentially an infinite size black body which radiates, I think you could heat your house at least through the winter. 🙂

  7. Bill says:

    I wonder if this technology could be applied to the cool end of a Stirling engine and reduce the size of the cooling components.

  8. R. Frist says:

    Wishful Thinking
    If they succeed in getting this system to work think how strange things would be. Everything at temperatures over absolute zero emits some black body infrared radiation. In the winter just put some of these magic antennas outside in the snow and use the power to run an electric space heater in the house. It would usher in a new world with new physical laws. You would be able to use the same energy over an over, heat to electricity and back to heat after turning a motor or lighting a lamp.

  9. Tom says:

    Nano Antenna
    I feel the nano techology have to be supported more by getting it’s possible contributions out to the public via radio, TV, magazines etc. I have contacted Nova Science Now to do a program about this technology. The more press, and the more people hear about the different potential applications for this technology, hopefully funding for fast tracking this technology will occur which will help get it to market in a cost effective timely manner.

  10. Ramsey Frist says:

    This clearly violates the 2nd law of the
    If such a device could work one could use it to transfer energy from one body to another even if both started at the same temperature and were both in an insulated box. This does not happen in our universe. How did they get funding for this project? Maybe its a cover for some sort of stealth technology.

  11. Stefano says:

    original paper
    sorry here it is :- http://www.inl.gov/pdfs/nantenna.pdf

  12. Stefano says:

    orignal paper
    Here is the link to original paper ;D http://www.inl.gov/pdfs/nanoantennas_science.pdf

  13. Stefano says:

    I just hope in what I read. It would be a living dream on Earth

  14. boband says:

    It is always appropriate to take a skeptical position…but it seems that this concept and the basis for it is widely known. Radio antennnas are no leap of faith. The potential efficiencies are also probably well known…and no doubt do not violate any laws of thermodynamics.

    I am generally a skeptic…but this idea seems to make sense to me. The problem with generating useful electricity from it, for example, is far from solved. But perhaps the heat transfer applications are much easier to solve – I don’t know.

    And, no doubt, this work is going on in many places, as implied in parts of the original article. I doubt that U of Idaho or anyone is taking exclusive credit for it. They may have made some progress in making it practical…and that is what they seem to be claiming.

  15. Katmandu says:

    Not entirely true….
    First off, he isn’t a DR… he doesn’t have a PhD – he has a Masters in Environmental Engineering. Did you ask if he can verify the existence of the nano antennas on that piece of gold sheet? He’d be lying if he says he can. Oh, and that nice image of the spiral antennas is courtesy of Univ. of Central Florida – it was THEIR work, not the lab’s. Lastly, any real scientist would tell you that this is so far-fetched it is crazy AND it helps if you don’t steal your colleague’s ideas and life work in the process to create a name and buck for yourself, Dr. Novack!

  16. Sara Prentice says:

    Video on nanoantenna
    At Idaho National Laboratory we have produced a video on the solar nanoantenna technology. You can view it at:


  17. Rosa R. says:

    I’d also like to thank Dr. Steven Novack at the Idaho National Laboratory and colleagues for making such a tremendous breakthrough!!!! Thankyou Hank chief geek for bringing us this incredible piece of news!!!! Love you both for both of your contributions to a better/smarter world! 🙂

  18. Rosa R. says:

    Just found out about you and I want to s
    I found this site today (April 26, 2008-Sat) by accidentally stumbling upon Yahoo!Green a few days ago! This is a very cool site! Thankyou Hank!! Great stories!!! and links!

    (always a fan of the environment and making sure I take it upon myself to learn more and more, and be able to use that knowledge for the better!)

  19. davie says:

    carpenter’s helper
    Geez, what a horrid bit i left above. I do insist none the less, that this subject seems a wonder filled learning/teaching vehicle. In defense of my crappy bit above: Emphasis was on the Imagining, just for the hope of jogging someone into a better idea. Thanks for the free platform!


  20. davie says:

    Carpenter’s Helper
    Hello Hank Green and All Others,

    I came to your article via jb’s sustainabledesignupdate website, thanks, John Barrie!

    Having read and reread Farrington Daniels’s book: Direct Use of the Sun’s Energy, Revised 1974 many times, my first impression upon reading Hank Green’s Ecogeek piece was : selective radiation coatings times quantum leap, then, as reading proceeded, it all reminded me of the heatpipe first encountered in Sci.Amer.magazine. A nanoscale heatpipe would have a minimum size of pipe sufficiently large to accomodate the requirements of the given working fluid which must pass through a transition from a vapor state to a liquid state and travel the length of the pipe by capillary action to complete a working cycle by being vaporized again by the heat input and passing the length of the pipe again, in the opposite direction, as a molecule of vapor at molecular speed. A heatpipe is able to conduct heat the length of the pipe at a far greater efficiency than the best of solid conductors.
    What I imagined is that the nantenna is accomplishing a transfer and transformation of energy utilizing electrons in a role like a working fluid plays in a heat pipe, in so far as it goes between the recieving and emitting ends of the system. This might be wrong: the nantenna might be imagined as a single molecule that accepts the energy of electromagnetic energy on one end and emits a ray of some nearly equivalent or less energy out the other end–that is, without electrons flowing through some intermediary conducting medium. Of course the imaginable possibility exists that nantennas require some conveyance between the receiving and emitting which could be some plasma stuff like solar wind in a magnetic field,for all I do not know. All I really know is that sixty cents U.S. times 2 sq.ft. worth of gold with the possibility of substiting other metals albeit no doubt with trade-offable efficiencies, rings like an economically viable proposition to me. I for one will be trecking along the links and references to be learning more…the “mind blowing” as someone upstream put it, possibilities at least for sci fi are right there fo sho. Well, also, the Hank Green piece is getting a second read here now…
    if you will excuse me, presently adding a new favorite..

  21. John says:

    Energy from nowhere (and your chicks for
    That low energy photon in, high energy photon out trick may sound like magic, but it doesn’t necessarily violate energy conservation.

    The conversion device is a mystery of course, but there are things like voltage doublers and hydraulic rams that convert high volume at low pressure into low volume at high pressure, no laws of physics violated. Perhaps the same thing can be done with photons…

  22. Eric says:

    Did he say…
    EG: On that very exciting note, I’ll just ask if you can think of any way to help our world stay sustainable.

    SN: My personal hope is that we decrease world suck by increasing availability of resources so that people can have a better life. There’s a direct correlation there. And, of course, I’d love to see more emphasis put onto funding this type of work.

  23. Virgil says:

    Wavelength shifting?
    I’m kinda curious as to how this actually works at the molecular level. There are molecules and technologies that will increase the wavelength of electromagnetic radiation. For example, fluorescent dyes will accept light of a particular wavelength (say green) and emit light at a longer wavelength (say red). This is a lower energy emission than what was put in, because the longer wavelength light has lower energy.

    As far as I know, the wavelength shifts achievable by such molecules are pretty small (on the order of a hundred nanometers maximum). It therefore seems implausible that you can shift wavelength by several hundreds or even thousands of nanometers, as would be required for example to turn light into heat or back again.

    Of course, there’s also the other issue that no-one has yet found a way to decrease wavelength (i.e. increase energy) in an efficient way. You can’t just put in a low energy photon (like infra-red), and get a high energy photon (like visible light or x-rays) without some extra energy input. It can’t simply be a 1:1 photon conversion process! It is thermodynamically impossible. Now, there is such thing as 2-photon or even 4-photon fluoresence, and that might be how this works. In that process, 2 photons of low energy (say 600nm) will excite the molecule at half-wavelength (i.e. 300nm) and it will emit at a longer wavelength than excited (say 400nM). However, the maximum efficiency achievable by this is 50%, because you need to put in 2 photons to get one out.

    Unless this guy has figured out a way to make energy out of nowhere, call me a skeptic I don’t buy all this resonance/vibration crap. How the hell do you put in low-energy photons and get out high energy photons? Where does the energy come from?

  24. Mamie Cosco says:

    The idea of cooling a room with nanoantennas reminds me of the need to increase availability of resources so people can have a better life.

    I always say a prayer and drink to world peace.

  25. Jane Porter says:

    interesting indeed…
    Thanks for highlighting this interesting technology.

    We need all the different approaches we can get to fight off fossil fuels.

    Looking forward to hearing more about this as the technology progresses.



  26. mr
    i have an eco friendly myspace page. on the right i have a link to a picasa web album where i’ve scanned my sketches but one of the drawings is for a nantenna or facsimile. i want you to see it and have it for the benefit of mankind. f-=well here’s the link to the picture – live long and prosper.