Easy-To-Manufacture, Thin-Film Solar Cell With Higher Than 15% Conversion Efficiency Created From Perovskites

October 4th, 2013 by James Ayre

Originally published on CleanTechnica sister site Ecopreneurist.

An easy-to-manufacture, thin-film solar cell with a higher than 15% conversion efficiency was recently created by researchers at the University of Oxford through the use of a newly emerging type of semiconductor referred to as “perovskites.” The new devices are simple enough that they could be mass produced rather easily, by utilizing processes such as vapour-deposition — potentially greatly cutting down on costs, according to the researchers.

The “perovskite” semiconductors — organometal trihalide perovskite semiconductors, which have the formula (CH3NH3)PbX3, with X being iodine, bromine, or chlorine — are relatively new to the solar energy field, having been first employed in solar cells only back in 2009. And while those first attempts to utilize them were relatively impressive, those initial results have now been surpassed, thanks to a simpler, new device that possesses a solar-to-electric power efficiency of 15.4% and a large ‘open circuit’ voltage of 1.07 V.

Image Credit: Boshu Zhang, Wong Choon Lim Glenn & Mingzhen Liu

“Our devices have a high solar-to-electric power efficiency of 15.4% and a large ‘open circuit’ voltage of 1.07 V – all in a solar cell in which the absorbing perovskite layer is only 330 nm thick,” states lead research Michael Johnston. “This means that we only need a tiny amount of perovskite material to make a solar cell with good properties.” (Conventional crystalline silicon cells, by comparison, are much thicker — usually ~0.15 mm — and produce less voltage — ~0.7 V under open-circuit conditions.)

“Little is known about the photophysics of these materials, which I think is quite exciting – this is a rapidly evolving field,” Johnston continues. “The fact that we can make such good solar cells using a conventional planar p–i–n architecture indicates that the charge-carrier diffusion lengths (the distances electrons and holes travel before recombining) are long, and that these carriers survive a long time in perovskite. That we can fabricate an efficient device without complex mesostructuring – as was previously the case with solar cells made from this material – also shows that perovskite is very good at both absorbing light and transporting photogenerated charge.”

Physics World provides more info:

According to the researchers, these perovskite-based devices should be cheap to make using processes that are compatible with existing solar-cell manufacturing infrastructures. And since they absorb light in a different part of the electromagnetic spectrum to silicon, the two materials might be used together in so-called tandem cells in which a silicon device would be placed underneath a perovskite one.

The researchers are now working to optimize the technology. Johnston explains: “I think we will see the efficiencies of these devices climbing higher in the near future. Investigations into the fundamental photophysics of the perovskite layers will be particularly interesting and will also help us accelerate the optimization process.”

The new research was published in the journal Nature.

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Tags: Easy to manufacture thin film solar cells, Organometal trihalide perovskite semiconductors, perovskites photovoltaics, thin-film solar 15% efficiency, thin-film solar cells University of Oxford, thin-film solar perovskites, TiO2 thin-film solar, University of Oxford

About the Author

James Ayre 's background is predominantly in geopolitics and history, but he has an obsessive interest in pretty much everything. After an early life spent in the Imperial Free City of Dortmund, James followed the river Ruhr to Cofbuokheim, where he attended the University of Astnide. And where he also briefly considered entering the coal mining business. He currently writes for a living, on a broad variety of subjects, ranging from science, to politics, to military history, to renewable energy. You can follow his work on Google+.

dcard88

My guess is current think film (the 15′ lengths) are about 8% so this would allow them to double the output when they start mfg in a couple years.
- mds
  
  I wonder is this stuff holds up better under high heat over decades of use. 8% amorphous silicon PV has some problems there. Might make the stick-on PV rolls and PV shingles much more viable …big maybe for now.
mds

Wow! Incredible! How stable? 30 years stable?
Lets see: 22% N type cSi layered on/under 15% perovskite …for maybe >30% efficiency at maybe very low cost. Wow! When?
- Jouni Valkonen
  
  it is extremly long way from university research paper to actual commercial product. So do not wow yet.
  - mds
    
    Normally I’d agree, but IF this is stable under accelerate sun exposure tests AND IF it is competitively cheap to produce at volume, THEN you should see this on the market in a few short years.
    Consider the market now. The largest and most successful CdTe producer, First Solar, is producing ThinFilm panels that are 13% efficient. FSLR hopes to make 15% panels by 2015. Of course, the 15% perovskite is a cell, not a panel and a percent or so will be lost in-between. …and it is from the lab not from production. Solar Frontier, the leader in CIS/CIGS, is at 14.5% panels now, at probably a higher production cost than FSLR. (Although who really knows, they ain’t talkin that I’ve seen.)
    You may be right. Those are big IFs and more often they get bigger, not smaller. Still Solar PV is a fast growing market with huge max potential. I don’t think any of the Solar PV technologies have improved this rapidly. This is a real eye opener. I’m sticking with my wow for now ;-).
    This is one of the reasons I read this junk. Very, very exciting.
    Who was it that was commenting that Solar PV has already reached maturity as an energy technology. Expect no more new improvements? Yeh, right! Too cool!
    I’m nominating this for post of the year.
    - Jouni Valkonen
      
      there are similar solar (and battery) breakthrough articles posted in Cleantechnica about once per month. There are no special wowness in this particular article.
      
      Good ideas are very rarely leading into actual commercial product.
      - mds
        
        You’re just going to rain on my parade aren’t you?
        Yes, I know all that. It is still a banged breakthrough! …and it MIGHT make it to production. pppththththtttt!
      - mds
        
        btw I looked up the rate of efficiency improvement for other Solar PV chemistries on the Wikipedia chart:
        http://en.wikipedia.org/wiki/File:Best_Research-Cell_Efficiencies.png
        It looks to me like multi-junction PV is the only one that has improved its’ efficiency at anywhere close to this perovskite PV material. Add to that the fact you might be able to multi-layer it will cSi and you officially have a breakthrough, a major breakthrough. If this makes it past economic and technical wickets to production, we’ll have an astonishing improvement. Big IF, but still amazing!
      - mds
        
        Correction:
        Said:
        “It looks to me like multi-junction PV is the only one that has improved it’s efficiency at anywhere close to this perovskite PV material.”
        Meant to say:
        “It looks to me like multi-junction PV is the only one that has improved its’ efficiency at anywhere close to the rate this perovskite PV material has been improved.”
        It’s the rate of improvement in the efficiency that is remarkable. They only just came with the idea to use this stuff a few years ago. Already they are at 15%. If it commercializes this easily and if its stable enough …wow!
    - JamesWimberley
      
      Possibly me. But what I´ve been saying is that we don´t *need* new cell technologies for the energy transition, in response to a common PR meme for ¨breakthrough¨ announcements. They will of course be very welcome if they do come.
      
      It´s very interesting that the Oxford researchers (my alma mater!) are already getting commercially competitive efficiency from a new process they admit not to understand very well.
      - Bob_Wallace
        
        Maturity does not mean a cessation of growth. It just means “good enough, even if it doesn’t get better”.
        
        I’m with James. Our PV technology is good enough. China is installing for around $1/watt. Do that in the US (and we can) and we greatly drop the cost of peak hour electricity, pulling down the overall cost of grid electricity. That, in my book, is “good enough”.
        
        Obviously, better will not be chased out of town.
        
        Some friends of fossil fuels use the “let’s wait for better technology” in an attempt to slow down the movement away from fossil fuels. There’s no reason to wait.
      - mds
        
        No, I disagree, “maturity” means to me that it’s cost effectiveness is leveling out and the technical improvements have most been squeezed out. Nothing could be further from the truth for Solar PV. We are not talking about some minor mitigation in cost by using Solar PV instead of fossil fuels. We’re actually talking about Solar PV blowing away almost any of the other competition. End-of-grid wise in a few areas right now. Source-of-gird too in some markets right now. End-of-grid AND source-of-grid throughout most of the globe in the not-to-distant future. Not parity. Half the cost of other alternatives or less (with the possible exception of wind) in areas with reasonable solar resources, which is most of the populated world. Sorry, I’m rambling again. I think this is an important argument for Solar PV. This idea that Solar PV is about as cost effective as it’s going to get now is balderdash and you should watch that you do not help perpetuate this foolish idea. The bogus “Breakthrough Institute” is already working that area of FUD for you. Look it up. With respect for both of you on this, and please let me know if you think I’m wrong, please watch your step on this.
        
        As to “good enough already”, absolutely! I’m in violent agreement with both of you there. “Never let better be the enemy of good.” You’ll sit around doing nothing the rest of your life if you do that. Conversely, never let good enough be the enemy of great… although that later is less important because it that tends to take care of itself.
        
        I respectfully suggest that both those views are equally important and equally valid.
        
        This is good evidence AGAIN that Solar PV will continue to become more cost effective. We can and should start saving money by using less fossil fuels RIGHT NOW, but we will benefit even more in the near future.
        
        Sorry, but THIS IS A BREAKTHROUGH guys! Maybe it never makes it to the market, maybe it does make it. In either case, it PROVES Solar PV can still do better in the future.
        Off to earn my daily bread. I’ll check in later. Cheers!
      - Bob_Wallace
        
        I suppose we need to add a qualifier to “mature”. I think solar is mature enough to make widespread installation cost effective. I don’t disagree that the final “maturity” of solar in terms of efficiency and cost is somewhere in the future.
        
        There are a number of potential advances coming. That means that over time electricity will get cheaper and it will take less money to replace fossil fuels.
        
        It’s all good….
      - mds
        
        Thanks, sorry to be so agressive. I have a little passion for the Solar PV revolution. I’m sure you’ve never noticed that.
        Good? Bob, we’re talking Solar PV here! It’s effing GREAT!
        chao
      - JamesWimberley
        
        We should stop arguing since we agree on the essentials.
      - mds
        
        Who’s arguing? We’re discussing, reaching a new and better consensus. (Besides, it’s fun discussing the tactics for the winning game and we are winning.) Don’t get jaded about these Solar PV breakthroughs. They may, or may not, make it to the market, but they demonstrate there is still plenty of potential for improvement in the cost effectiveness of Solar PV. This is very important because it is good evidence that Solar PV will continue to improve well past the current tipping point. Solar PV is bringing a disruptive change to electric power generation, nothing less.
        
        For anyone worried we might move backwards in this effort, forget it. Solar PV will only be moving forward, slower or faster, but forward.
        
        btw I looked up the rate of efficiency improvement for other Solar PV chemistries on the Wikipedia chart:
        http://en.wikipedia.org/wiki/File:Best_Research-Cell_Efficiencies.png
        It looks to me like multi-junction PV is the only one that has improved it’s efficiency at anywhere close to this perovskite PV material. Add to that the fact you might be able to multi-layer it will cSi and you officially have a breakthrough, a major breakthrough. If this makes it past economic and technical wickets to production, we’ll have an astonishing improvement. Big IF, but still amazing!
        Embrace it! I command you!
      - jaybee
        
        Hmmm, now if we could just mature the cost of installation a bit and make widespread adoption an affordable venture for many more passionate solar pv people
      - mds
        
        Exactimundo! Steady as she goes. We’re progressing two years behind the Germans. We’ll make it just fine.
      - mds
        
        Correction:
        Said:
        “It looks to me like multi-junction PV is the only one that has improved it’s efficiency at anywhere close to this perovskite PV material.”
        
        Meant to say:
        “It looks to me like multi-junction PV is the only one that has improved its’ efficiency at anywhere close to the rate this perovskite PV material has been improved.”
        It’s the rate of improvement in the efficiency that is remarkable. They only just came with the idea to use this stuff a few years ago. Already they are at 15%. If it commercializes this easily and if its stable enough …wow!