Tokyo--Dow Chemical, which is rapidly expanding its footprint in green, has taken an equity investment in Nuvosun, a start-up focused on copper indium gallium selenide (CIGS) solar cells.

Nuvosun CEO Dave Pearce wouldn't say how large the investment is, but it's been made, he told me at the Cleantech Open Innovation Summit sponsored by JAIC America in Tokyo.  (JAIC is part of the Japan Asia Investment Co. and specializes in Japanese-U.S. investments).

Pearce worked with Dow when he was at Miasole, another CIGS manufacturer. Miasole and Dow were working on solar panels. Miasole dropped out of the deal. Dow lined up with Global Solar and will come out with solar roofing tiles later this year.

Founded in 1897 (William McKinley was President then), Dow has made a number of moves in the past year to exploit its material science know-how in various green markets. Last September, Dow Corning, a joint venture between Dow and Corning, brought a silicone sealant originally devised for outer space solar panels to the conventional solar panel market. Silicone protects better than standard coatings, the company said, but also increases factory output. In November, Dow signed a multimillion dollar, multi-year research alliance with Caltech to develop next generation solar technologies. Secretive Alta Devices (working on a next generation solar cell) and Soliant (concentrators) have come out of Caltech.

It also has a development deal with in BioPetroClean, which has found a way to use bacteria to clean water fouled by oil and other contaminants. Dow bought Rohm & Haas to expand into water and next week will sponsor Electric Avenue, the electric car hall at the North American International Auto Show taking place in Detroit. The exhibit will feature 20 cars. Dow Kokam, a joint venture, will also discuss batteries for electric cars at the show.

Dow isn't alone among large, old companies getting into green. Philips, Pansonic, Toshiba, TSMC, Samung, LG and others are all devising strategies and opening the wallet to go green. Start-ups have ideas, conglomerates have factories and cash. It's like a May-September romance.

Nuvosun's secret sauce in CIGS is a precursor, post-selenization process that it combines with chemical plating. In this, the copper, indium and gallium are deposited in a fairly cold process. Selenium is added in a later high temperature process. Nanosolar has a two stage process that it combines with printing.

"The two-step process gives you more individual control. CIGS is all about determining the right reaction pathways," Pearce told us last year. "You can form all sorts of subspecies you don't want."

Last year, the company came up with a test cell that was 11.8 percent efficient, which is in line with what other CIGS companies have reported for early, experimental cells. Nuvosun, however, has spent a lot less money to get there. It bought some of the equipment for its prototype factory off eBay. Some of the early CIGS companies raised hundreds of millions of dollars-a lot of that money got spent on devising manufacturing processes. Now, the processes are a little better understood so the cost of starting a CIGS outfit has declined. Telio Solar also built some CIGS cells for relatively little money. Granted, the early entrants like Nanosolar have a head start, but the emergence of these smaller companies bears watching.

More on Nuvosun in this here video taken at their factory.