Clean Power Perovskite solar cells Brown University

Published on March 17th, 2015 | by Tina Casey

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US Taxpayers Deserve Huge Group Hug For New Perovskite Solar Cell Breakthrough

March 17th, 2015 by  

With a big assist from the National Renewable Energy Laboratory in Colorado, a team of Brown University researchers has developed a new process for making solar cells based on the crystalline material perovskite. Early testing shows a solar conversion efficiency of more than 15%, which is pretty impressive for a first try, and to ice the cake, the process can be used to make a semitransparent solar cell film that could be used in windows and other see-through applications.

If Brown University isn’t the first institution that pops up when you think of clean energy, no worries. Compared to some other institutions, the school has been flying under our radar, but we have covered its forays into tidal energy and graphene, so now let’s give perovskite a go.

Perovskite solar cells Brown University

What Is This Perovskite You Speak Of?

For those of you new to the topic, perovskite refers to a class of crystals that are among the most abundant materials in the world, if not the most abundant. The first example was discovered in the Ural mountains back in 1839.

Conventional solar cells are based on silicon, and perovskites could offer a much cheaper way to get the same — or better — conversion efficiency, so if you think solar energy is giving fossil fuels a run for the money now, just wait until researchers work out some of the kinks involved in making perovskite solar cells.

We went to our friends over at the University of Surrey for some more details about perovskite. Here is a relevant snippet:

Some Perovskites are superconductors! This is where a material can conduct electricity with no resistance at all — it would revolutionalise technology if a room-temperature superconductor was found — at the moment they all operate at very low temperatures.

Perovskites could also be useful in advanced fuel cells and batteries for electric vehicles, but we digress.



The Brown University Perovskite Breakthrough

Typically, perovskite thin-film solar cells are made with an energy-intensive high-temperature process. It’s a finicky, time-consuming approach that can leave “pinholes” in the film, cutting down on efficiency.

Since the film is built up from a substrate, the high temperature also means that you can’t use low-cost, flexible materials like plastics.

The new Brown University perovskite solar cell process goes in an entirely different direction.

The team developed a way to fabricate a thin-film solar cell at room temperature, which they’re calling SSE for solvent-solvent extraction.

Don’t try this at home, but the steps look simple enough:

...perovskite precursors are dissolved in a solvent called NMP and coated onto a substrate. Then, instead of heating, the substrate is bathed in diethyl ether (DEE), a second solvent that selectively grabs the NMP solvent and whisks it away. What’s left is an ultra-smooth film of perovskite crystals.

According to Brown, the entire process only takes a couple of minutes, compared to the hour-long range required for high-temperature processes.

The result is a high-quality thin film without pinholes down to the 20-nanometer range, compared to 300 nanometers required for typical perovskite solar cell films.

At 80 nanometers, the Brown researchers also claim that their perovskite thin-film is more efficient than any other ultra-thin film.

The film is transparent enough to use as a building-integrated solar substitute for windows or glass walls. The team has already tweaked the solvents to create different colors, which would open up a wider range of applications to attract architects and designers.

Also helping things along is the team’s assertion that the process easily lends itself to an assembly line setup, which would help cut manufacturing costs to the bone.

Many Paths To A Perovskite Future

If only Mr. McGuire had said “perovskites” instead of “plastics” way back in 1967, Benjamin and all the rest of us could be swimming in perovskite solar products by now, but instead we’ll have to wait a few more years.

Meanwhile, speaking of group hugs for US taxpayers, the National Renewable Energy Laboratory is just one of several publicly funded R&D facilities working on perovskites.

Over at Los Alamos National Laboratory, for example, researchers are developing a perovskite solar cell approaching 18% efficiency, and they are also working on a low-cost, high-efficiency process for “growing” perovskite solar cells.

The rapid drop in the cost of solar over the past few years is clearly making the fossil competition nervous. If you then consider up-and-coming research like Brown’s, it looks like it’s going to get very interesting soon.

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Photo Credit (photo enhanced): Courtesy of Padture Lab/Brown University.


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About the Author

specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.



  • Andrew West

    “The rapid drop in the cost of solar over the past few years is clearly making the fossil competition nervous.”

    Silly. After five decades, energy production from solar energy is .3% in the US. That doesn’t make anyone nervous OR hopeful.

    Great research. But, nothing in the research about production cost, as usual.

    • Andy

      Don’t forget about exponential growth.

    • Kyle Field

      If you’re looking at 5 decades worth and still not seeing the recent trend in the last few years you may be missing something. Check out the graph below and see if you can pick up on it… http://upload.wikimedia.org/wikipedia/commons/thumb/7/72/US_Solar_Electricity_Production.svg/1024px-US_Solar_Electricity_Production.svg.png

      • Andrew West

        .3%, one third of one percent.

        • Philip W

          Ever heard of exponential growth?

        • Kyle Field

          Yes, the trend in the last 5 years is what’s really driving the excitement. Also, looks like your data is off by 50%. How’s that Exxon stock doing? BP? Last name Koch?

          “In the twelve months through December 2014, utility scale solar power generated 18.32 terawatt-hours (TWh), 0.45% of total U.S. electricity.”

          • Andrew West

            Like I said, .3% of “energy use,” I didn’t say electricity. It is and will continue to be an insignificant amount of our energy supply. And the recent growth is highly subsidized, something that isn’t sustainable.

            I know solar cheerleaders have trouble with that reality, but it’s insignificant.

          • Sweetie

            Andrew, news flash: fossil fuel is highly subsidized, something that isn’t sustainable, either!

          • Bob_Wallace

            Let’s back that up with a picture.

        • Bob_Wallace

          Andrew, you’re looking foolish.

          Rapid growth follows prices reaching the tipping point.

          BTW, probably more than 1% in the US in 2014 if end-user generation is included. Utility side of the grid was 0.45% in 2014. Up 96% from 2013.

          Look for a major increase in 2015.

          • Andrew West

            Even if it’s 1% it is insignificant. The only ones benefitting are the solar cheerleaders misleading the public. It’s just delusional.

          • Bob_Wallace

            You’ve made your very insignificant observation, Andrew.

            No one is impressed.

            Now, would you like to contribute meaningful content or prefer to go away?

          • Andrew West

            Poor Bob. That’s all you have?

            Solar cheerleaders just hate the facts. The incentives expire soon, cheer louder.

          • Bob_Wallace

            Andrew, make your next contribution meaningful or it will be your last on this site.

            Capish?

          • Andrew West

            Oh, you censor comments? I guess the expressed fact that “solar is insignificant” is a reason to censor someone is the policy at Cleantechnica?

            Grow up. Defend your ideas. Use math. Make your case.

            Solar energy is less than .3% and $100 billion. That’s a waste of money.

          • Bob_Wallace

            That was about half acceptable.

            Try again.

          • Andrew West

            And that’s the only math you have?

          • Bob_Wallace

            What numbers interest you, Andrew?

            Here’s how electricity produced with solar has grown through 2014.

            And here’s how solar prices and PPA contract prices have been dropping.

            There’s a tipping point for most transitions before which change is slow. Once the tipping point is reached change accelerates. As you can see, between 2011 and the end of 2014 things changed.

      • H Stick

        Hocky stick graph!!

    • Radical Ignorant

      Sad for them if they can only look in the past.

  • BarrySaxifrage

    Can you grow food with the light that passes through the Perovskite panels? If so there is a lot of acreage that could do double duty.

  • Michael G

    Perovskite suerconductors is what caught my eye. That is actually a potential for incredibly efficient energy storage and is currently in use in Wisconsin to smooth the rapid demand spikes at saw mills.

    • Matt

      “room temperature superconductors” think I heard that one before. The devil is for sure in those details.

    • Kyle Field

      Let me know when you’re ready for that cup o joe and we can get this thing moving (if that’s all it takes :D). But seriously…I’m excited to see what this innovation brings to superconducting as well – quick discharge for EVs accelerating? grid scale superconductive storage to absorb daily usage spikes? yeah, there’s some serious potential on multiple fronts stemming from this single innovation.

  • There have been countless of supposed solar revolutions that never get out of the lab. I’m not getting my hopes up on this one yet.

    • Will E

      I remember a rotating printing machine
      printing meters of
      solar cells, could be done at home or at the printshop in the street. never happened.
      but never try never win, so maybe this is a winner.
      big hug.

      • Adrian

        That was the hope of Nanosolar, but unfortunately they couldn’t scale-up the process quickly enough to compete against the rapidly dropping costs of silicon process cells.

    • Papa

      Also countless solar patents that have paid off. 80% drop in price since 2008 is quite a revolution.

      • Kyle Field

        True. Everything has changed in the last 5 years even with solar. Excited to see what perovskites bring to the fold in the next 5 (ok, so it will probably take 5 years to see anything come to market…but still :D)

    • Kyle Field

      There comes a point in any innovation where we have to lean forward…to trust what seems to good to be true. At this point, all they’re asking is…nothing! It’s funded with what seems to be the major innovation out of the way. The rest is the easy part – integration into existing applications, fine tuning of efficiencies…heck, they’re already working on different colors…

  • jburt56

    Vertical PV–overcomes land use objections.

    • Forget vertical, there is still so much untapped potential on the existing horizontal built environment. Look outside your window. How many parking lots, streets, and roofs are taking advantage of solar?

      • Mark

        High density places like New York/Japan can benefit from vertical. The horizontal already has competitive technology, which is improving, and it will eventually be everywhere. They only have so much capacity for making cells anyway.

    • Kyle Field

      I haven’t heard of this as a specific use case other than building integrated. More specifically – I have not seen panels intentionally designed to be mounted vertically. There’s a building in Santa Monica, CA with vertical panels on the side but it’s more of an aesthetic brag than functional. Curious to see if/when/how this market shapes up.

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