IBM develops promising contender for cheaper solar cells

Feb 11, 2010 by Lin Edwards report
Magnified view of a cross section of the compound Cu2ZnSn(S,Se)4.

(PhysOrg.com) -- Solar cells could make fossil fuels virtually redundant if they were cheaper, but their use of rare elements and complex manufacturing processes makes them expensive. Now IBM Research has developed a prototype solar cell that solves both problems, using common, cheap elements and using an inexpensive manufacturing process. Their paper is published in the Advanced Materials journal.

The new are known as “kesterite” cells, which are produced using a printing technology in which a solution containing nanoparticles is spin-coated onto a glass substrate. According to IBM their efficiency is close to that of established solar cells.

IBM researcher David Mitzi, who is also manager of the company’s photovoltaic science and technology department, said they wanted to reduce the cost and use more abundant elements for thin-film photovoltaic cells. The current technology uses the rare elements indium and tellurium. is in particularly short supply because it is also used in the manufacture of transparent transistors and is in high demand for flat panel display systems. By contrast IBM’s kesterite cells uses the common elements tin (Sn), zinc (Zn), copper (Cu), selenium (Se), and sulfur (S).

The new solar cells are also cheaper to manufacture, using a “printing” technique that uses a hydrazine solution containing copper and tin with of zinc dispersed within it. The solution is then spin-coated and heat treated in the presence of selenium or sulfur vapor. This process is much cheaper than the traditional , which uses an expensive vacuum-based technique.

IBM's solar cell device.

A team at the Nagaoka National College of Technology in Japan produced a thin-film kesterite cell in 2009, which had an efficiency of 6.8 per cent. IBM’s kesterite cell has increased the efficiency by 40 per cent. Mitzi said they are planning to increase the efficiency above 11 per cent, which is equal to or better than the traditional solar cells.

contribute under 0.1 per cent of the Earth’s electricity supply at the moment, largely due to their expense and the rarity of their key elements. The IBM solar cell could change all of that. IBM will patent and license the technology and says it is open to partnerships with existing photovoltaic cell manufacturers to bring it to the market.

Explore further: Microfluidics and nanofluidics research provide inexpensive ways to analyze blood and filter water (w/ Video)

More information:
-- High-Efficiency Solar Cell with Earth-Abundant Liquid-Processed Absorber, Advanced Materials, DOI:10.1002/adma.200904155
-- IBM's Smarter Planet Blog

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Birger
5 / 5 (2) Feb 11, 2010
Very interesting -but it will be nice to have an estimate of the cost per energy unit for mass-produced solar cells (taking into consideration that solar cells do not produce electricity for 24 hours)
ThomasS
5 / 5 (3) Feb 11, 2010
not bad, 11% efficiency with common elements and a printing procedure.. especially with IBM's big arm behind it..
Zarp
2 / 5 (8) Feb 11, 2010
"using a “printing” technique that uses a hydrazine solution"

A little problem - hydrazine is extremely toxic, even in aqueous solution.

From http://en.wikiped...ydrazine
Hydrazine is highly toxic and dangerously unstable with autoignition temperature 24-270 C.
It means, it can be easily ignited even at room temperature or a bit higher.

Also wrom Wiki: "On February 21, 2008, the United States government destroyed the disabled spy satellite USA 193 with a sea-launched missile, reportedly due to the potential danger of a hydrazine release if it re-entered the Earth's atmosphere intact"

They even destroy satellites, containing hydrazine fuel, before they reach the Earth atmosphere. How can solar cell, containig such material, be called a "green tech"? Pb and Cd are a way less dangerous but they aren't used in modern electronics due to RoHS requirements (at least in EU).
fmfbrestel
5 / 5 (6) Feb 11, 2010
Hydrazine is used in the solution used to print the chips, and is not a component of the chip itself. This is painfully obvious. quit trolling.
SteveL
5 / 5 (2) Feb 11, 2010
Copper and zinc are also becomming more expensive due in large part to the increasing demand by developed and developing economies. This is an excellent step on the path to a viable solution.

I say, keep up the good work.
jet
5 / 5 (3) Feb 11, 2010
"A little problem - hydrazine is extremely toxic, even in aqueous solution"

But Gallium Arsenide is ok with you ?
Zarp
1.4 / 5 (9) Feb 11, 2010
"Hydrazine is used in the solution used to print the chips, and is not a component of the chip itself"
... but the workers will be exposed to it during the production for a substantial time. There are a lot of people agitating against using silicon in solar cells just because the production involves hazardous substances. The same arguments can be applied here.

"But Gallium Arsenide is ok with you ?"
Nope, and that's one of the reasons why it is NOT used on a large scale (the other reason - higher costs)
JayK
3 / 5 (3) Feb 11, 2010
Do you understand anything about the manufacturing of semiconductors as is done today, all over the world, Zarp? Some of the chemical compounds located in fabrications are deadly at 1:1000000 concentrations to large amounts of people if dispersed into a local water supply.

They know what they're doing in these places. OSHA and other regulations make sure that containment and transportation of these chemicals happens in redundantly safe manners. You on the other hand, obviously have no clue.
jselin
4.5 / 5 (2) Feb 11, 2010
"Hydrazine is used in the solution used to print the chips, and is not a component of the chip itself"
... but the workers will be exposed to it during the production for a substantial time. There are a lot of people agitating against using silicon in solar cells just because the production involves hazardous substances. The same arguments can be applied here.

"But Gallium Arsenide is ok with you ?"
Nope, and that's one of the reasons why it is NOT used on a large scale (the other reason - higher costs)


At the risk of sounding foolish, toxicity is overrated IMHO. Develop an effective containment plan and stick to it. Screen workers. Move forward.

JayK
2 / 5 (2) Feb 11, 2010
Gallium Arsenide is used around the world for manufacturing of semiconductors as well, Zarp.

Take a few seconds to do Google searches before you post, please.
Sonhouse
4 / 5 (2) Feb 11, 2010
"A little problem - hydrazine is extremely toxic, even in aqueous solution"

But Gallium Arsenide is ok with you ?

Or HF acids, sulphuric acid, pure arsenic, phosphorus, and the like used in ion implanters as dopants? I know those very well, I spent 20 years as an ion implant field service engineer. I'll take my chances with the hydrazine. Or how about the gold deposition process using cyanide?
AdrianMiller
5 / 5 (3) Feb 12, 2010
Thanks for the interest in this work! If anyone would like to know more about the science behind this story (and it sounds like a lot of you might do!) we've set the original research paper as free to access; you can find it here: http://www.materi...412/TEXT

Adrian Miller
Advanced Materials
RolfRomeo
2.3 / 5 (3) Feb 12, 2010
High tech is high tox.

I believe this to be inevitable.
JayK
3.7 / 5 (3) Feb 12, 2010
High tech is high tox.

I believe this to be inevitable.


Do you have a point? The manufacturing of many of the materials you use everyday include chemicals that have toxicities.
Skeptic_Heretic
5 / 5 (1) Feb 12, 2010
High tech is high tox.

I believe this to be inevitable.

Along with JayK's statement, the inherent toxicity of all manufactured goods is a result of their natural toxicity.

Mercury isn't edible if you dug it up, is it?

But that's an overly simplistic view. Toxicity is what it is, and to affix manufacture as the reason for it is ridiculous.
theken101
5 / 5 (1) Feb 15, 2010
"They even destroy satellites, containing hydrazine fuel, before they reach the Earth atmosphere."

Actually, the US destroyed the spy satellite because it was a BRAND-NEW SPY SATELLITE, not because it contained hydrazine. There was no way they could risk a foreign government getting their hands on any part of it...
AAhhzz01
5 / 5 (1) Feb 16, 2010
Hydrazine is used in the on board power units of the F-16....how many hundreds of those would you say are scattered around the world these days? How often are you hearing horror tales of dozens, hundreds or thousands mained or killed by hydrazine accidents daily...oh thats right...it isnt happening that often is it...

Hydrazine..
Toxic? Yes.
Dangerous? Yes.
Useful and safe when handled by trained personnel? Yes

That sattilite would have never reached ground with any hydrazine left...That could not have been the reason for destroying it...but was a convienent cover story wasnt it?

Point, hydrazine has it's dangers, but when used under proper conditions by trained personnel it presents minimal risk. Any good safety officer could set up the operation to minimize those risks and have approperate emergency response in place to deal with the situation when things go all pear shaped.
arrowrod
3 / 5 (1) Feb 18, 2010
Wow, a exceptional achievement. With other manufacturers claiming $1 a watt soon, This may drive solar panels to $.5 a watt. I'll be energy self sufficient (as long as I have nano-technology to store energy doing the day).
Skeptic_Heretic
5 / 5 (1) Feb 18, 2010
Just an FYI: Hydrazine is also a component of Visine, the eye care solution.

As has been said before everything is toxic in the wrong amount.
seneca
5 / 5 (2) Feb 18, 2010
Hydrazine is safely used in closed production cycle and most of residue will decompose during subsequent thermal treatment. In life environment hydrazine is oxidized rapidly to harmless nitrogen. In fact it's quite environmentally clean fuel and reducing agent, commonly used as oxygen scavenger in boiler feedwater to inhibit corrosion. A huge amount of hydrazine is used in semiconductor industry already and nobody cares about it.