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Subject:  Solar Breakthrough? Date:  2/14/2012  12:43 AM
Author:  DCWD40 Number:  18016 of 18435

I have been following the solar industry since 1967. The only big, big thing over the years has been First Solar's ability to get more and more out of its CdTe technology. Others have had CdTe as their focus (like Shell) but all the oil money in the world has not been able to match First Solar growth and profitability.

Tonight I see that one of the solar companies I have followed for the last 20 years has made a breakthrough. Sumitomo Chemical, a Japanese company, has a new infrared-absorbing polymer material that has been rumored to greatly increase the efficiency of multi-layer solar cells. The Sumitomo Chemical product has finally worked its magic:

In the effort to convert sunlight into electricity, photovoltaic solar cells that use conductive organic polymers for light absorption and conversion have shown great potential. Organic polymers can be produced in high volumes at low cost, resulting in photovoltaic devices that are cheap, lightweight and flexible.

In a new study, available online this week in the journal Nature Photonics, researchers at the UCLA Henry Samueli School of Engineering and Applied Science and UCLA's California Nanosystems Institute (CNSI) report that they have significantly enhanced polymer solar cells' performance by building a device with a new "tandem" structure that combines multiple cells with different absorption bands. The device had a certified power-conversion efficiency of 8.62 percent and set a world record in July 2011.

Further, after the researchers incorporated a new infrared-absorbing polymer material provided by Sumitomo Chemical of Japan into the device, the device's architecture proved to be widely applicable and the power-conversion efficiency jumped to 10.6 percent — a new record — as certified by the U.S. Department of Energy's National Renewable Energy Laboratory.


http://www.physorg.com/news/2012-02-tandem-polymer-solar-cel...

Organic polymers have been thought to be one of the next big challenges to First Solar's technology (although CIGS and CIS-alloys are being produced today with big-money backing). But, cheap manufacturing and 8.6% solar efficiency isn't going to cut it for organic polymers. At 10.6%, though, there is now light at the end of the organic tunnel.

First Solar is headed for 20% efficiency with its current technology. Does the flexibility, ruggedness, and friendly environmental impact of organics make them a potentially better total cost option? How about 15% efficiency?

This study opens up a new direction for polymer chemists to pursue designs of new materials for tandem polymer solar cells. Furthermore, it indicates an important step towards the commercialization of polymer solar cells. Yang said his team hopes to reach 15 percent efficiency in the next few years.

At 15%, organics start to become a no-brainer when compared to CdTe technology. Why? This is old news to people on this board:

Another issue frequently mentioned, is the use and recycling of the extremely toxic metal cadmium, one of the six most toxic materials banned by European Union's RoHS regulation. According to First Solar's annual report, the CdTe solar panel is not in RoHS compliance, not listed in the exemption product list, but not currently listed in the restricted product list either. So the product's future RoHS compliance status is uncertain.

http://en.wikipedia.org/wiki/Cadmium_telluride_photovoltaics...

An environmentally friend competitor could get cadmium under the regulator's spotlight. There is also this old news:

Perhaps the most subtle and least understood problem with CdTe PV is the supply of tellurium. Tellurium (Te) is an element not currently used for many applications. Only a small amount, estimated to be about 800 metric tons per year, is available. According to USGS, global tellurium production in 2007 was 135 metric tons. Most of it comes as a by-product of copper, with smaller byproduct amounts from lead and gold. One gigawatt (GW) of CdTe PV modules would require about 93 metric tons (at current efficiencies and thicknesses), so this seems like a limiting factor. However, because tellurium has had so few uses, it has not been the focus of geologic exploration.

If you read all the Wikipedia material, you will see mitigating factors for both cadmium and tellurium. But, the toxic chemicals that get mentioned by First Solar when talking about competing products (things First Solar doesn't use), are probably not a problem with organic polymers.

Sumitomo Chemcial's stock hasn't been a big winner for anyone for years. It's recent restructuring efforts to increase margins has been needed but hasn't ignited the stock. Organic polymers might be the fire that finally gets this company back on its feet.

Where Sumitomo got its technology will make some Fools chuckle if they own PANL. Sumitomo Chemical in 2007 acquired UK-based Cambridge Display Technology, a pioneer in the development of polymer organic LEDs and related devices. This is the company were Sumitomo's polymers were probably discovered.

First Solar's stock has been pummeled. I like its growth prospects for the coming years although I have never owned the shares. But, it is always good to know where the bumps in the road are. Organic polymers were a non-issue a year ago when it comes to 5-year threats. That is no longer true.

W.D.
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