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Toward Cheaper, Robust Solar Cells

Researchers are working on solar cells that use a novel organic dye.

By Prachi Patel

Thursday, March 13, 2008
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Cheap and easy-to-make dye-sensitized solar cells are still in the early stages of commercial production. Meanwhile, their inventor, Michael Gratzel, is working on more advanced versions of them. In a paper published in the online edition of Angewandte Chemie, Gratzel, a chemistry professor at the École Polytechnique Fédérale de Lausanne in Switzerland, presents a version of dye-sensitized cells that could be more robust and even cheaper to make than current versions.

Making solar cheaper: Dye-sensitized solar cells, which are cheaper than silicon cells, consist of dye-coated titanium dioxide nanoparticles immersed in an electrolyte solution, which is sandwiched between glass plates. A new combination of electrolyte and dye promises to make these solar cells even cheaper and more robust. Key to the innovation is an organic dye molecule.
Credit: Alex Agrios, Northwestern University

Dye-sensitized solar cells consist of titanium oxide nanocrystals that are coated with light-absorbing dye molecules and immersed in an electrolyte solution, which is sandwiched between two glass plates or embedded in plastic. Light striking the dye frees electrons and creates "holes"--the areas of positive charge that result when electrons are lost. The semiconducting titanium dioxide particles collect the electrons and transfer them to an external circuit, producing an electric current.

These solar cells are cheaper to make than conventional silicon photovoltaic panels. In principle, they could be used to make power-generating windows and building facades, and they could even be incorporated into clothing. (See "Window Power" and "Solar Cells for Cheap.") A Lowell, MA-based company called Konarka is manufacturing dye-sensitized solar cells in a limited quantity. But the technology still has room for improvement.

Story continues below


In existing versions of the solar cells, the electrolyte solution uses organic solvents. When the solar cells reach high temperatures, the solvent can evaporate and start to leak out. Researchers are now looking at a type of material that may make a better electrolyte: ionic liquids, which are currently used as industrial solvents. These liquids do not evaporate at solar-cell operating temperatures. "Ionic liquids are less volatile and more robust," says Bruce Parkinson, a chemistry professor at Colorado State University.

New dyes are also being investigated. In commercial cells, the dyes are made of the precious metal ruthenium. But researchers have recently started to consider organic molecules as an alternative. "Organic dyes will become important because they can be cheaply made," Gratzel says. In the long run, they might also be more abundant than ruthenium.

Tags

nanocrystals photovoltaics solar cells

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Comments
  • $/KWH
    The holy grail.

    What's it all translate to, in delivered $/KWH.
    Rate this comment: 12345

    nekote
    03/13/2008
    Posts:139
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    3/5
  • Novel idea .
    Why not use charcoal particles suspended in water in glass tubes as a means of absorbing solar energy in a solar thermal style . The dark colour of the charcoal would convert the energy in to heat then electricity much more efficiently than photovoltaic . Comments welcome .

    Note to self : Remember to give self a five star rating for this comment .
    Rate this comment: 12345

    DJTal
    03/13/2008
    Posts:133
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    • Re: Novel idea .
      Possible. It's very possible. Do you have figures on the efficiency?
      Rate this comment: 12345

      protn7
      03/13/2008
      Posts:69
      Avg Rating:
      2/5
    • Re: Novel idea .
      While charcoal (essentially acting as a black body) would do a much better job of utilizing solar energy than PV for direct heat purposes, it would probably lose out for electrical generation.

      Using solar energy to drive a heat engine is a dandy idea but the problem is achieving adequate Carnot efficiencies, power densities, and capital efficiency ($/W). With no/low concentrations this does not appear to be an achievable goal. High concentration units, however, perform well with this concept.
      Rate this comment: 12345

      GreenPlease
      03/16/2008
      Posts:7
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      4/5
    • Re: Novel idea .
      If these cells are to be used as an alternative energy source, using and making charcoal to absorb photons ultimately defeats the goal of reducing carbon dioxide emissions.
      Rate this comment: 12345

      matlseng
      11/23/2009
      Posts:2
  • Semiconductive Polymer
    Perhaps Bell Lab's Intercept Technology resin would be a better substrate than the coated TiO2.  It is extrudable and is a semiconductor often used as a superior ESD packaging protection.
    Rate this comment: 12345

    RD
    03/13/2008
    Posts:114
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  • Funding
    I wonder how much funding is really in place for this kind of research?  All of these technologies seem to struggle around 10% efficiency when they would be "home runs" if they were within striking range of 20%.

    If there were a serious commitment to get there, 2X doesn't seem that hard -- worth a moon shot kind of effort considering the possible consequences of having to rely on coal to meet our future energy needs.

    I wish the candidates would start debating this instead of whether OB is sexist or Hillary is racist or McCain is holy enough.
    Rate this comment: 12345

    GaryB
    03/13/2008
    Posts:65
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    4/5
    • Re: Funding
      What's the lifetime of those babes? And the dye components? http://vulvox.triod.com protn7@att.net
      Rate this comment: 12345

      protn7
      03/13/2008
      Posts:69
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      2/5
      • Re: Funding
        Vulvox my company has a program on the drawing board; an 80% efficiency solar cell based on technology that is going off patent next year. We plan to test more practical versions of Alvin Mark's lumeloid concept. Contact Neil Farbstein protn7@att.net
        Rate this comment: 12345

        protn7
        03/13/2008
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        • Re: Funding
          80%! You have got to be kidding . Isn't that beyond the maximum theoretical efficiency or something .
          Rate this comment: 12345

          DJTal
          03/14/2008
          Posts:133
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          • Re: Funding
            Theoretical limits depend on the structure used. Most single material limits are around 30% but using multiple materials that capture at different layers that push that up to between 50-70%.  I would say that efficiencies at 30-40% would be more realistic and cost effective in the next decade.  Hopefully one day we will reach mass availability of the higher efficiencies.
            Rate this comment: 12345

            jaggspb
            03/14/2008
            Posts:9
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            3/5
            • Re: Funding
              High efficiency concentrator cells have demonstrated about 43 percent at about 20 suns. These are very expensive and thus only suitable for high concentration ratios, but 20 suns is relatively low for the concentrator industry so that's impressive. Still, they are not as efficient under one sun.

              Amorphous diamond could be over 50% efficient, and possibly be very cheap. It's hypothetical at this point of course, but the science is valid. Cooling under higher concentrations would be easier due to the high temperature resistance and extraordinary conductivity of diamond.

              Infrared nano antennas could be 80%, but as of yet no practical 'inverter' has been found. Maybe capacitors.

              The theoretical limit to the photovoltaic effect is around 97-98%, but for a long time to come there will be material constraints that prohibit approaching those levels, especially in a commercial product.
              Rate this comment: 12345

              Siphon
              03/28/2008
              Posts:145
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          • Re: Funding
            Neil Farbstein, so called president of Vulvox, isn't kidding, but he is lying. He gets lots of practice at this. He makes wild claims of impossible breakthroughs on many different technology websites. But if you look for any, they don't exist.
            Rate this comment: 12345

            N O M
            08/20/2008
            Posts:23
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            4/5
  • Hybrid concentrated solar photovoltaic
    Has anyone combined these two technologies? Could concentrated solar be retrofitted with photovoltaic when it becomes more economical?
    Rate this comment: 12345

    ronwagn
    03/17/2008
    Posts:23
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    • Re: Hybrid concentrated solar photovoltaic
      Might be nice for a peaker plant, but not for a high capacity plant as you would lose the cheap and simple storage benefit that solar thermal has.

      It could be a great idea if electrical storage becomes cheaper. Superconducting magnetic storage, ultracaps etc. My favorite is no-fuel CAES as this could prove to be efficient and quite workable.

      I prefer trying to increase the efficiency of the power block though, so the cheap storage benefit of solar thermal remains exploitable. Maybe those infrared nano antennas or more efficient thermoelectrics...
      Rate this comment: 12345

      Siphon
      03/28/2008
      Posts:145
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  • Lumeloid TM & Quensor TM
    I find it humerous to read about Neil Farbstein from Vulvox is working on Lumeloid TM Technologies that were invented by my father the late Dr. Alvin M. Marks. The Research and Development of Lumeloid is being pursued by my company and we plan on filing a new patent once prototype development has been completed. It is possible to get 80% efficiency out of Lumeloid TM according to our calculations and current principles of rectifying antenna theory. Experiments in other labs have confirmed this. There are other labs that are working on a similar approach to Lumeloid, but it has become obvious to me that the original inventors approach is the most logical to getting anywhere near 80% conversion. Some of our calculations point to a possible 100% conversion is possible. Calculation and theory are quite different than the R&D that will lead to a working prototype. Only further investigation into this area will confirm what my father has claimed in Lumeloid and Quensor as it has never been done before. I further note that key chemistry and process elements were never included by my father in the original patent filed in "86 and the improvement patent filed in "93 # 5,229,624. I would further like to state that Farbstein had contacted me personally and it is my opinion that this guy makes wild claims and project affiliations to technologies and Intellectual Property that he has nothing to do with whatsoever. My father's last patent #122 Quensor TM #6,501,093 issued in 2002, a high density quantum energy storage or retrieval device will soon start initial R&D through my company once adequate funding is secured. Both these technologies require many-millions in investment for R&D to reach prototypes and commercial applications. There is no doubt to anyone involved in these areas that if Dr. Marks technologies prove successful that it would revolutionize the Alternative Energy and Storage fields. A simple internet search will lead you to information on the status of both technologies as well as a www.uspto.gov search on ownership.
    Rate this comment: 12345

    Technitron
    09/26/2008
    Posts:2
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    4/5
    • Re: Lumeloid TM & Quensor TM
      It's not humorous at all.
      Why is this guy trying to ruin my reputation?
      His diatribe discusses the old patents his father got that are all out of date in in the public domain. Anyone can use the lumeloid technology now that his patents have expired.
      He attempts to erect a smokescreen and make it seem he still has a research program going by talking about his irrelevant quensor patent. It's not related, it's a capacitor type device that, like the lumeloid IP, has never been tested. I did meet Alvin Marks' son in a restaurant in New York City in the Village. I still have the phony literature he gave me. No working prototype of the quensor or the lumeloid devices have ever been constructed. This guy is a real failure living on his father's money, his father is senile he is his care taker. He blew his chance to exploit his father's intellectual property and the lumloid patents are now in the public domain. He spent a million and half trying to design a prototype a year before the patent expired and his program is total loser. Now other's are refining his invention and the royalty money will go to them.
      But why is ruining my professional reputation?
      Why did he write "I would further like to state that Farbstein had contacted me personally and it is my opinion that this guy makes wild claims and project affiliations to technologies and Intellectual Property that he has nothing to do with whatsoever. " I will tell you he is slandering an important scientist. Its nobody's business what transpired the one time we met. Anyone who divulges private information like that is obviously committing libelous acts.

      I told him Dr. Tom Netzel, the former President of the American Chemical Society wrote a technical review of my nanoelectronics project and stated it is a great invention that might change the world in innumerable ways if the project is funded. He offered to work on it in his lab if i got the funding. I have that letter if anyone wants to see it. I have others like his review too.

      What this guy has is a libel and slander suit against him. Hey Technitron! I'm putting you on notice now that if you dont retract your remarks and apologize I will sue you and have you prosecuted to the fullest extent of the law. Any lawyers willing to sue him are encouraged to contact me at protn7@att.net
      Rate this comment: 12345

      protn7
      11/07/2008
      Posts:69
      Avg Rating:
      2/5
      • Re: Lumeloid TM & Quensor TM
        What professional reputation Farbstein?

        The only reputation you have is as a lying fraud who spams tech forums. Your so-called company has no employees, yet you style yourself as its president.

        You have threatened many lawsuits, yet how you will manage one on an anonymous forum has never been explained. You have even claimed to be sueing NASA for 100s of millions of dollars, but this was a lie.
        ... Oh, you did have a case thrown out for wasting court time when you tried to sue a library for banning you.
        Rate this comment: 12345

        N O M
        06/09/2009
        Posts:23
        Avg Rating:
        4/5
        • Re: Lumeloid TM & Quensor TM
          I can't believe that anyone gives any serious thought or consideration to anything Neil Farbswine comments on or his ridiculous technology and patent claims. Its pretty funny about the lunch meet as he was seeking information on my father's wind fence technology, which I explained to him that it would take billions in funding to complete as Dr. Marks had envisioned it and that it was not anything I or my father was working on. The wind-fence technology has been in public domain since the late 90's. He claimed he had personal funds through his company Vulvox that he wanted to fund and collaborate on my Lumeloid TM project, which turned out to be false. When I met the guy at a sushi place I like to eat at he came across as mentally challenged and off his meds. I cut the meeting after 15 minutes as I could detect that the guy was nuts and needed some serious mental health services. He started hitting on one of the waitresses and was bagging up the left-overs even mine as I was leaving. He ordered enough food for 3 people on my dime. I later had to apologize for his rude behavior to the owner of the sushi joint in Midtown and explain that he lured me into a meeting under false pretenses. I learned a valuable lesson, never meet anyone for lunch on business until after you do a google search on them. It is true that the improvement patent for Lumeloid TM has gone into public domain, but the trade-secrets and know-how were never disclosed in the prior art of the patents. As soon as samples are completed an improvement patent will be filed. Its not a major concern of mine as I have stated the Trade-Secrets and Know-How were never disclosed in the original patent or the improvement patent. I am teamed with a major University and a non-profit solar organization in NY State to complete the Lumeloid TM project. If our grant funding comes through this year you could expect to see a commercial product in 3-5 years. I am also working on securing the funding to move the Quensor TM technology forward. I don't know why this guy makes all these ridiculous claims as an inventor and Scientist for technologies he has absolutely nothing to do with. He must have some kind of mental disorder. I hope no one else gets suckered into meeting this guy for any prospected business he claims to be involved in. I'm just glad he did not try to assassinate me at his free lunch cause that's how he comes across if you ever have the misfortune of meeting this guy. Neil you should get a hobby not related to Science and Technology and please take your meds for the sanity of others who have to read your nutzoid comments and posts. Also my father Dr. Alvin M. Marks passed away on May 25th, 2008 at the age of 97 and there was a full page obituary in the NY TIMES listing all the accomplishments and technologies he patented over his career. It is also true that I cared for my father personally for 5 years as I could not place my father in a nursing home as I loved him dearly and nursing homes are awful. Those 5 years were 5 of the most interesting and memorable years of my life. My father was a great man and its an honor to continue his R&D of Lumeloid TM and Quensor TM. This will be my last reply to Farbstein related nonsense as obviously I am very busy pushing these technologies forward for the eventual benefit of all.
          Rate this comment: 12345

          Technitron
          06/19/2009
          Posts:2
          Avg Rating:
          4/5
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