Organic solar cell developer Heliatek has raised $27 million to build its first factory amid the debate whether these sort of cells will every constitute a major market.

The German company said it raised the second-round from venture capital firms such as Wellington Partners, RWE Innogy Ventures, BASF Venture Capital, as well as industrial giant Bosch.

Founded in 2006 as a spinoff of the Universities of Dresden and Ulm, Heliatek plans to use the money to build a factory in Dresden to produce solar panels featuring cells that are made with hydrocarbon-based organic dyes. The dyes, by the way, involve materials co-developed with German chemical giant, BASF.

As its name suggests, organic solar cells make use of carbon and other organic materials to make inks or dyes for converting sunlight into electricity. The technology holds promise, its advocates say, because both the organic materials and the process of depositing them onto flexible backings could be had cheaply.

Solar panels made with organic cells also have a much lighter weight than most of the solar panels on the market today. Heliatek said its solar panels would weigh 500 grams per square meter, compared with 20 kilograms per square meter in other solar panels.

Skeptics doubt that organic solar cells would achieve mass appeal given its low efficiencies – it's not able to convert sunlight into electricity at the same rates as a host of other types of technologies, from the commonly found crystalline silicon solar cells to the emerging thin films that use semiconductor compounds such as copper, indium, gallium and selenium. Durability is also an open question.

Some of the better-known organic solar cell developers include Konarka Technologies, which has struggled for years to find a market for its product. The Lowell, Mass.-based company hopes to find customers who would embed Konarka's cells into building materials (see Konarka Runs 'Solar Curtain Wall' Pilot).

Meanwhile, chip giant Intel, whose research interests include renewable energy, has dispatched researchers to investigate ways to improve organic solar cells' efficiencies (see Organic Photovoltaics With Intel Inside?).

Organic solar cell development remains largely in the pre-commercialization stage, but the technology has attracted no shortage of investors. Back in August this year, Plextronics in Pittsburgh said it had raised $14 million for developing  solar cells and organic light emitting diodes. Part of that funding came from the investment arm of the Brussels-based chemical and pharmaceutical company, Solvay Group. 

Organic solar cell developers collectively have about 5 megawatts of production capacity worldwide in 2009, according to GTM Research. The capacity isn't expected to grow much in 2010, but may expand to about a gigawatt by 2012.

Heliatek was able to fabricate sample cells that could convert 6.07 percent of the sunlight that falls on them into electricity, the company said. The Fraunhofer Institute for Solar Energy Systems verified the efficiency, Helitak said in August.

The company received seed funding of €500,000 from High-Tech Gründerfonds and €100,000 from co-founder Herald Eggers.

Photo via Heliatek.