A new world record for solar cell efficiency

Jan 17, 2013
High-efficiency flexible CIGS solar cells on polyimide film were developed at Empa with a novel process. Credit: Empa

In a remarkable feat, scientists at Empa, the Swiss Federal Laboratories for Materials Science and Technology, have developed thin film solar cells on flexible polymer foils with a new record efficiency of 20.4 percent for converting sunlight into electricity. The cells are based on CIGS semiconducting material known for its potential to provide cost-effective solar electricity. The technology is currently awaiting scale-up for industrial applications.

To make affordable on a large scale, scientists and engineers the world over have long been trying to develop a low-cost solar cell, which is both highly efficient and easy to manufacture with high throughput. Now a team at Empa's Laboratory for Thin Film and Photovoltaics, led by Ayodhya N. Tiwari, has made (yet another) leap ahead. They achieved a record 20.4% for thin film CIGS solar cells on substrates, a massive improvement over the previous record of 18.7% achieved by the same team in May 2011. Tiwari's team has been investigating and developing various thin film solar cell technologies for some time. Over the years the laboratory has boosted the photovoltaic conversion efficiency of flexible CIGS solar cells time and again, from 12.8% in 1999 – the group's first world record – to 14.1% in 2005, 17.6% in 2010 and 18.7% in 2011.

Closing the efficiency gap to silicon wafer cells

The latest in the series of records has been achieved, thanks to innovative ideas and excellent team work in the lab, especially by PhD students Adrian Chirila and Fabian Pianezzi. The team has succeeded in modifying the properties of the CIGS layer, grown at low temperatures, which absorbs light and contributes to the photo-current in solar cells. The cell efficiency value was independently certified by the Fraunhofer Institute for (ISE) in Freiburg, Germany. What's more, Empa's new record efficiency for flexible solar cells now even exceeds the record value of 20.3% for CIGS solar cells on glass substrates – and equals the highest efficiencies for polycrystalline silicon wafer-based solar cells. "We have now – finally – managed to close the "efficiency gap" to solar cells based on polycrystalline or CIGS thin film cells on glass", says Tiwari.

Thin film, lightweight and flexible high-performance solar modules are attractive for numerous applications such as solar farms, roofs and facades of buildings, automobiles and portable electronics and can be produced using continuous roll-to-roll manufacturing processes that offer further cost reductions compared to standard silicon technologies. In other words, they have the potential to enable low-cost solar electricity in the near future. "The series of record efficiencies for flexible CIGS solar cells developed at Empa demonstrates that can match the excellent performance of polycrystalline silicon cells. Now it is time for the next step, the scale-up of the technology to cover large areas in a cost-efficient roll-to-roll manufacturing process with an industrial partner", says Gian-Luca Bona the Director of Empa. For this purpose, Empa is collaborating with Flisom, a start-up company involved in industrialization of flexible CIGS .

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antialias_physorg
3.9 / 5 (15) Jan 17, 2013
Whenever I look at the various efficiencies of solar cells I think we've come a very long way in just a few decades.
http://en.wikiped...U%29.jpg

When paired with the breathtaking drop in cost of manufacture from the earliest cells that's a pretty good achievement.
jscroft
3.3 / 5 (12) Jan 17, 2013
Yah this is huge. Great work!
VendicarD
2.3 / 5 (3) Jan 17, 2013
rare earths?
baudrunner
1.5 / 5 (6) Jan 17, 2013
I would like to see a cross-section of the film. If it is simply a flat thin film, then that efficiency can be increased even further by channeling specially shaped grooves in the surface that bounce light around in them.
wealthychef
4.6 / 5 (10) Jan 17, 2013
My favorite part of the article is the following, something rarely heard in these kind of "breakthrough" article: "Now it is time for the next step, the scale-up of the technology to cover large areas.." You mean they're actually going to make these and they will be used? Awesome! I'll believe it when I see it! :-)
packrat
3.2 / 5 (9) Jan 17, 2013
My favorite part of the article is the following, something rarely heard in these kind of "breakthrough" article: "Now it is time for the next step, the scale-up of the technology to cover large areas.." You mean they're actually going to make these and they will be used? Awesome! I'll believe it when I see it! :-)


I agree with you! It seems like a new breakthrough is made about every 6 months or less but you don't ever see them available to buy. It's always 5-10 years down the road.......
qitana
not rated yet Jan 17, 2013
interesting,

CIGS apparently stands for CuIn1-xGaxSe2

could one have a good reduction in cost compared to 'traditional' solar cells if these metals are used?
VendicarD
1 / 5 (1) Jan 17, 2013
In
dirk_bruere
5 / 5 (4) Jan 17, 2013
In 20 years time our cities will be black with PV cladding of every large surface
RealScience
5 / 5 (3) Jan 17, 2013
@gitana - The active layer is only about one micron thick (100 times THINNER than an ordinary sheet of paper), so the amount of these expensive metals used is actually quite small.
It comes down to the processing cost more than the materials cost.
djr
4 / 5 (4) Jan 18, 2013
Anatalias: "Whenever I look at the various efficiencies of solar cells I think we've come a very long way in just a few decades."

Very true - and counter to so many of the posts on this board - renewables are pulling the price of electricity down. Look at this story about German power costs tumbling as a result of solar. http://www.bloomb...sts.html

Imagine what that means for power costs in 10 or 20 years!!!!
lengould100
5 / 5 (1) Jan 18, 2013
... counter to so many of the posts on this board - renewables are pulling the price of electricity down. Look at this story about German power costs tumbling as a result of solar. http://www.bloomb...sts.html

Imagine what that means for power costs in 10 or 20 years!!!!

I expect that the only way present installations in Germany are reducing electricity prices is because of high up-front capital subsidies. Solar PV is not (yet) anywhere near as low-cost as coal or nuclear. Don't get me wrong, I'd love to see it happen, but know it is not there yet. And the present economic downturn in Europe is going to cause a large further delay. Sorry. One only needs to look at the history of this group's record-breaking development to become concerned. A low-material flexible thin-film solar cell with only 10% or 11% effic. would be fantastic, yet this group is claiming they had 12.8% in 1999. ???
Marcos_Toledo
1.7 / 5 (6) Jan 18, 2013
Looking forward to a 75% to 90% efficency rate of solar electric cells for powering homes as soon as possibile.
antialias_physorg
3.3 / 5 (10) Jan 18, 2013
Look at this story about German power costs tumbling as a result of solar.

Yes, I caught a similar article yesterday. The big power companies are massively unhappy about this because it's starting to eat into their profits. Seems like the fat years when they could overcharge us for power are over.

I expect that the only way present installations in Germany are reducing electricity prices is because of high up-front capital subsidies.

EVERY new power source got massive subsidies. Coal got it. Nuclear got it. Why should alternative energies not get it?

And if you look at the numbers (in adjusted Euros): Coal got to date 210bn Euros. Nuclear got 180bn. All alternatives combined (including all future feed in tarrifs which are set down by law) got 30bn - and the alternative energy sources are already outproducing nuclear.

Now you tell me what is the better bang for the (tax)buck?
djr
4 / 5 (4) Jan 18, 2013
lengould: "Solar PV is not (yet) anywhere near as low-cost as coal or nuclear."

Well - you would have to define 'anywhere near' If you look at this chart -http://en.wikiped..._sources you see the cheapest power generation right now is natural gas. PV is about triple. Coal and Nuclear are in between. PV is falling fast - and in some markets around the world (look at Mexico) clearly competitive today. There is one factor you have to consider. My utility charges me 12 cents (U.S) per KWh. With the right orientation - home owners can install panels that translate into around 12 cents per KWh. You can't install a coal plant in your home and generate your own power. So from that perspective - PV is at grid parity today. Hang on for the ride. Anatalias is correct - the days of being monoplized by complacent utilities are numbered - hang on for the ride.
nathj72
5 / 5 (2) Jan 18, 2013
Good job demonstrating a high efficiency thin film solar cell. Too bad you used indium. Considering current high demand for indium, this is unlikely to be useful.
dschlink
4.3 / 5 (7) Jan 18, 2013
Almost a day before the first "cold fusion" comment. I think that's a record. No one has demonstrated a CF device that works reliably and can be duplicated by another lab.
lengould100
4.7 / 5 (3) Jan 18, 2013
Agreed dsclink: Cold fusion is a nutter tech. It's had lots of time to prove capability, and no result. Aside from the fact (overpersuasive imho), it has no technical backup presentable, it is entirely underpersuasive on a share investment basis.

Re: solar: It's still proven to me that solar thermal is about 3x more economical than solar PV (even given reduced input of solar reflectors vs. direct PV), anyone really wanting solar generation to replace fossil generation would be supporting solar thermal, yet the "downtown cognoscenti" refuse to support solar thermal, and the MINOR short-term subsidies it would need to compete with fossil.
sirchick
1 / 5 (2) Jan 19, 2013
My favorite part of the article is the following, something rarely heard in these kind of "breakthrough" article: "Now it is time for the next step, the scale-up of the technology to cover large areas.." You mean they're actually going to make these and they will be used? Awesome! I'll believe it when I see it! :-)


I agree with you! It seems like a new breakthrough is made about every 6 months or less but you don't ever see them available to buy. It's always 5-10 years down the road.......


Probably because of patent filling and protecting their designs to sell to business or something. At some point along the way business gets involved and drip feed the products to make maximum sales.

Have you seen the patent counts for graphene easily in the thousands already but sod all on sale or changing the world that I've seen yet.

We just have to be patient :(
Steve123
5 / 5 (3) Jan 19, 2013
Solar Thermal, with thermal storage and Natural Gas back up, will be a good supplement and commercially viable. There are a lot of plants already under construction and it is welcomed.

Flexible PV cells are good for niche applications but will be hard pressed to compete with what's already in place.

If they can compete with a reduced start up cost and operating efficiencies then they have a chance.

Otherwise they'll be stuck with a few nerds glueing it to the roof of their car to trickle charge their EV's.
RealScience
5 / 5 (3) Jan 19, 2013
It seems like a new breakthrough is made about every 6 months or less but you don't ever see them available to buy.


Probably because of patent filling and protecting their designs ... business gets involved and drip feed the products to make maximum sales.


I both invent and develop products, so I can answer from personal experience.

Development work on the most promising innovations typically doesn't wait for patents to be issued. Developing complex new products is simply a huge amount of work with no guarantee of even technical success (the devil is in the details, and nature always sides with the hidden flaw).

Inventions are like children - conceiving them is fun, but raising them to be successful is years of hard work. And in a field with so many inventions, they compete against each other and few make it to maturity. In a crowded field less than one invention in 100 becomes part of a successful product.
sirchick
not rated yet Jan 19, 2013
It seems like a new breakthrough is made about every 6 months or less but you don't ever see them available to buy.


Probably because of patent filling and protecting their designs ... business gets involved and drip feed the products to make maximum sales.


I both invent and develop products, so I can answer from personal experience.

Development work on the most promising innovations typically doesn't wait for patents to be issued. Developing complex new products is simply a huge amount of work with no guarantee of even technical success (the devil is in the details, and nature always sides with the hidden flaw).

Inventions are like children - conceiving them is fun, but raising them to be successful is years of hard work. And in a field with so many inventions, they compete against each other and few make it to maturity. In a crowded field less than one invention in 100 becomes part of a successful product.

Ah thanks for the insight :)
Egleton
1 / 5 (4) Jan 20, 2013
Agreed dsclink: Cold fusion is a nutter tech. It's had lots of time to prove capability, and no result.

Transistors had 1$Billion of research money thrown at them in order to figure out why they were unreliable.

I'll bet there was somebody just like you saying that transistors were nutter technology. But we we would not find his hand going up in confession now. As a matter of fact, I don't even know what his name is. Do you want to be that unknown critic?
Dr Edward Storms thinks that the Chinese will be selling in Walmart.
http://coldfusion...1-18.mp3
Eikka
1 / 5 (3) Jan 20, 2013
The big power companies are massively unhappy about this because it's starting to eat into their profits. Seems like the fat years when they could overcharge us for power are over.


The other angle of the story: because renewable energy has the right of way in the power grid, conventional power generation has to yield whenever the sun shines or the wind blows. This reduces the number of hours the conventional powerplants can operate, increasing the cost of investment per output, making the power more expensive.

In addition, when renewable energy does produce, it often causes a glut of power which forces the spot price of electricity down and forces others to sell at a loss.

Yet renewable sources are -dependent- on conventional production for 80% of the time, or the power grid would destabilize.

EVERY new power source got massive subsidies. Coal got it. Nuclear got it. Why should alternative energies not get it?


Because of lower energy gain per invested euro
Eikka
1 / 5 (2) Jan 20, 2013
There are exceptions of course, such as biogas and geothermal power, which work with instead of against the rest of the power grid.

But these are not the ones recieving the majority of subsidies in places like Germany, that are sinking massive amounts of money into solar and wind even though they generate almost nothing but trouble.
Eikka
2 / 5 (4) Jan 20, 2013
home owners can install panels that translate into around 12 cents per KWh.


Here's the rub:

You can only offset a small portion of your power with solar panels because they only operate a small portion of the day at full power.

Or, you can generate more power than you can use personally and try to sell it to offset more of your electricity cost, but with everyone doing the same thing, you're not going to get 12 cents a kWh because there's over-abundance right when you're trying to sell.

And it's the same thing on a state/national level as on a personal level. You can generate as much as you can handle, which isn't much, or you can try to sell the excess, which won't make you much money because the price has to be very low for anyone to buy it.

That's why you need subsidies to make it happen at all. The owners must be guaranteed money, and the taxpayers must foot the bill or solar panels just don't make any fiscal sense.
antialias_physorg
3 / 5 (2) Jan 20, 2013
But these are not the ones recieving the majority of subsidies in places like Germany, that are sinking massive amounts of money into solar and wind

Still only about 1/10th to 1/8th of what has been (and is being) sunk into coal or nuclear individually(!).
Alternatives are WAY ahead in the "electricity generated per tax euro spent"-game

So far ahead that it's almost hysterically funny.
RealScience
5 / 5 (2) Jan 20, 2013
@Eikka: While there is some validity to what you say, there are significant exceptions.
In areas where the peak demand is for air conditioning (LA Phoenix, LV, SanD), even photovoltaic solar makes it easier for fossil fuel plants by shaving the peak. Even more so in regions with water-limited hyrdro-electric sources, solar works cooperatively with the grid.

Once the demand peak is shaved, intermittent sources without storage DO indeed have the issues you describe. That's why the utilities are interested in solar-thermal-WITH-STORAGE, in spite of it (currently) costing more per Watt (or per kWh) than PV.
SteveL
not rated yet Jan 20, 2013
After procuring rights to technology the engineering phase has to begin to determine the best way to mass produce a technology product, including packaging, logistics and many many other aspects of successful production. If the engineering is wrong some other company will find a better way and you lose the tens of millions you invested. Also, while still doing the engineering another report comes out describing further advancements which will automatically put you out of business.

From solar cells to batteries the technology advances so fast it has to be tough to invest heavily in such technologies knowing that the next tech article you read can bankrupt you.
PoppaJ
1 / 5 (4) Jan 20, 2013
I am very familiar with applying thin films. It is not a loss less system. The large scale manufacturing cost will increase faster then the financial return (Rare Earth in gas form, hyper pure carrying gasses, quartz or ceramic chambers that will have very finite life spans, scrubber systems,) ((Any one who has worked in tech production just got a stomach ache.)). While the discovery is valuable it is still based on a very old process. Efficiency on large scale is going to be what determines how fast this will come to market.
SteveL
not rated yet Jan 20, 2013
I wonder how long these solar cells last, down to say 80% output. 20 years? I don't know. All the buzz is on output, not on life span.

For small community low temp solar my money is still on a pentane-rankin system using pumped water as the energy storage medium. Very effecient? No. Just reliable and should expect a longer life cycle.
packrat
1.8 / 5 (5) Jan 20, 2013
I wonder how long these solar cells last, down to say 80% output. 20 years? I don't know. All the buzz is on output, not on life span.

For small community low temp solar my money is still on a pentane-rankin system using pumped water as the energy storage medium. Very effecient? No. Just reliable and should expect a longer life cycle.


I've been working on those type of designs for a few years now. I think I've finally got one that will work for a well water pumping project I'm working on using just solar heated water. Still saving up to buy the needed bits to build it. Hopefully I'll have it done by this summer when the other half will need it for watering the garden. It should drop our water bill down quite a bit.
javjav
not rated yet Jan 20, 2013
a record 20.4% energy conversion efficiency for thin film CIGS solar cells on flexible polymer substrates, a massive improvement over the previous record of 18.7%

Since when a 2.7% percent improvement in the low end is a "massive improvement" .?. To start with it is not the absolute solar cells record as the title suggest. Just in a subcategory of lab only production , not real production which can not be done by now. A 2.7% improvement has to be measured in terms of costs, is it a real 2.7% reduction in solar energy cost? No. It isn't. This cell is more costly at this moment that others that are more efficient and less expensive by now. If you are in the low-cost market, no "massive " claims until you solve the manufacturing problem and compare costs, please.
antialias_physorg
5 / 5 (1) Jan 20, 2013
Since when a 2.7% percent improvement in the low end is a "massive improvement" .?

It's a massive improvement for this type of solar cell (thin film solar cell) which are massively cheaper than the monocrystalline/wafer-kind (and can also be put down on any kind of surface - not just a rigid/plane ones)

Just in a subcategory of lab only production , not real production which can not be done by now

This is a science site. Are you complaining that people report about science, here?

A 2.7% improvement has to be measured in terms of costs

Again. Science site. Remember?

And your claim that this ISN'T cost effective is just pulled out of some smelly place. You have nothing to back that up - so stop making claims that make you look like a fool.
javjav
not rated yet Jan 20, 2013
This is a science site. Are you complaining that people report about science, here?
No. I complain about journalist who not understand science writing about science.
And your claim that this ISN'T cost effective ...You have nothing to back that up
The article itself says it works in the lab but it is not cost effective for manufacturing yet!. Is not my claim. Please read the article before answering. Their claim is not a record in maximum efficiency, but a potential record in energy cost "if" they can produce it. Even if they solve manufacturing issues, a 2.7% efficiency can not translate into a -2.7% in energy costs as more than half cost is the transport, installation and maintenance. So maybe a 1% reduction, and only "if" they solve it, which is the complex part here. Solve it and then put the word "massive"
CIGS apparently stands for CuIn1-xGaxSe2 could one have a good reduction in cost compared to 'traditional' solar cells if these metals are used?
Exactly
javjav
not rated yet Jan 20, 2013
This is a science site. Are you complaining that people report about science, here?

Just to remark that I don't complain about the papers written by scientists at Empa (who are great BTW, although their breakthrough was past year, not the small step of today, so not so breaking news), my complain was only about the journalist work, and I was vey clear about it. The spectacular title "A new world record for solar cell efficiency", plus the terms "massive improvement", and "you look like a fool" have not been written by scientists but added later by amateur journalists, who are the people I complain about. Because this is not a tabloid newspaper but a science site, do you remember?

VendicarD
5 / 5 (1) Jan 20, 2013
Eikka is right.

"In addition, when renewable energy does produce, it often causes a glut of power which forces the spot price of electricity down and forces others to sell at a loss." - Eikka

Dollar based economics is the enemy of efficiency.
ValeriaT
1 / 5 (4) Jan 20, 2013
Dollar based economics is the enemy of efficiency.
It wouldn't be, if the USA would be economically most efficient country on the world, but they're losing this position gradually. The USA national debet as expressed in $100 bills...
sirchick
not rated yet Jan 20, 2013
It seems like a new breakthrough is made about every 6 months or less but you don't ever see them available to buy.

Probably because of patent filling and protecting their designs ... business gets involved and drip feed the products to make maximum sales.


I both invent and develop products, so I can answer from personal experience.

Development work on the most promising innovations typically doesn't wait for patents to be issued. Developing complex new products is simply a huge amount of work with no guarantee of even technical success (the devil is in the details, and nature always sides with the hidden flaw).

Inventions are like children - conceiving them is fun, but raising them to be successful is years of hard work. And in a field with so many inventions, they compete against each other and few make it to maturity. In a crowded field less than one invention in 100 becomes part of a successful product.


Ah thanks for the insight.
VendicarD
5 / 5 (1) Jan 21, 2013
That is an interesting view given the fact that the Chinese don't seem to be at all interested in Cold Fusion.

"Dr Edward Storms thinks that the Chinese will be selling in Walmart." - Egleton

Odd, isn't it?

You would think that if there was a market for it, they would be moving to dominate that market as they do with everything else.

Why do you think they are ignoring it?

Could it possibly be because it is a scam, like Martini and Rossi's Ecat scam?
VendicarD
5 / 5 (2) Jan 21, 2013
Money is a grand fiction.

Energy is not.

Those who value fiction over reality are unworthy fools.

"The owners must be guaranteed money, and the taxpayers must foot the bill or solar panels just don't make any fiscal sense." - Eikka
Birger
4.5 / 5 (2) Jan 21, 2013
Sure solar PV can only replace part of the electricity production, but considering the emerging negative effects of a coal/oil based electricity infrastructure every little bit helps. We cannot wait for large-scale fusion before we do something.
hb_
2.3 / 5 (3) Jan 21, 2013
Two things:

(1) How do the scientist propose to design a "roll-to-roll" process for the CIGS on a polymer foil? CIGS usually entails PVD and sputtering.. Can these be incorporated in a "roll-to-roll" process? I don't see how.
.
(2) What is the durability of these solar cells? A normal CIGS cell has glass in front and at the back; an excelent protection agains oxygen in the atmosphere. Now is the polymer (front and back) good enough? Will it degrade in sunlight?
Neinsense99
1 / 5 (4) Jan 21, 2013
Whether or not solar PV power is economically competitive depends on your location and situation. While natural gas and others may be presently cheaper as a global average, that does not mean it isn't already competitive in many locations and for many uses where the other options are impractical, or come with other downsides that don't appear so obviously on the bottom line. Want to be independent of the utility company? PV already outdoes nuclear/fossil fuels/hydroelectric there.
antialias_physorg
3 / 5 (2) Jan 21, 2013
because renewable energy has the right of way in the power grid, conventional power generation has to yield whenever the sun shines or the wind blows. This reduces the number of hours the conventional powerplants can operate, increasing the cost of investment per output, making the power more expensive.

The cheapest powet source wins. Power is bought and sold much like stocks as supply and demand indicate (accross borders, too)

Because of lower energy gain per invested euro

Less than 30bn subsidies for 22% electricity (from alternatives) as opposed to 180bn subsidies for 22% electricity (from nuclear) is "lower energy gain per invested Euro"?

How does THAT kind of math work on your planet?
2ndGreenRevolution Blog
1.8 / 5 (4) Jan 21, 2013
It's always nice to read about new advances in solar technology. 20.4 percent is a big leap. Though I wonder: for high-capacity solar projects, does fear of the "next big leap" being just around the corner delay the timing of solar installations?
lengould100
not rated yet Jan 21, 2013
I still wonder if it isn't a mistake to subsidize installations v.s. R&D? Perhaps governments should set 1 date each 5 years as an "R&D cutoff date", and the most cost-effective technology in each of several streams which has a ready record of production on that date gets subsidized (sort of a large government X Prize).
Valentiinro
not rated yet Jan 22, 2013

Shut up and take my money!
Eikka
1 / 5 (1) Jan 25, 2013
Still only about 1/10th to 1/8th of what has been (and is being) sunk into coal or nuclear individually(!).


Again, they may get 10 times the subsidies, but they make 100 times the energy.

The cheapest powet source wins. Power is bought and sold much like stocks as supply and demand indicate (accross borders, too)


Intermittent power does not work alone, so if it drives conventional power out of the grid by making it unprofitable, it also brings the grid down and nobody is getting any power then.

The alternative is that it actually increases the overall price of electricity because the demand for energy demands a supply of energy - despite the fact that the renewable energy itself is cheap.

Because for every one MWh of wind power at $40/MWh, you need another four MWh of other electricity at $300/MWh to adjust to the fluctuating supply of it. If it wasn't for the wind power, you could produce all the electricity far cheaper with conventional baseload technology.