Good ole’ anti-freeze, keeps your car’s engine from freezing and from overheating, but it may also be a critical component for developing next generation thin-film photovoltaics. At least that’s what researchers think. They recently published research in Material Letters showing that ethylene glycol could be a relatively cheap solvent that can help make solar cells less expensive and the process of making solar less toxic.

The research found that anti-freeze functions well as a solvent in “continuous flow” reactor, particularly for producing copper zinc tin sulfide (CZTS) based PV cells. The technology uses ethylene glycol in meso-fluidic reactors.

“The global use of solar energy may be held back if the materials we use to produce solar cells are too expensive or require the use of toxic chemicals in production,” said Greg Herman, an associate professor in the OSU School of Chemical, Biological and Environmental Engineering. “We need technologies that use abundant, inexpensive materials, preferably ones that can be mined in the U.S. This process offers that.”

The reactors can be fine-tuned to yield better crystal qualities by controlling temperature, reaction time, and mass transport. They also produce crystals much more quickly. According to the university, the traditional “batch mode” method of making copper indium gallium diselenide-based (CIGS) PV cells, which can take a day. The continuous flow model can produce PV cells in about a half hour.

The researchers said the process could easily be scaled up for mass production, and that such PV cells could essentially be cooked in a microwave oven. “For large-scale industrial production, all of these factors—cost of materials, speed, quality control—can translate into money,” Herman said. “The approach we’re using should provide high-quality solar cells at a lower cost.”

The university compared the CTZS cells with CIGS PV cells—one of the most promising thin-film PV cells available today. “Indium is comparatively rare and costly, and mostly produced in China,” it said. “Last year, the prices of indium and gallium used in CIGS solar cells were about 275 times higher than the zinc used in CZTS cells.” In addition, the CZTS-based PV materials are abundant and largely benign.

Still, CZTS-based PV is much less efficient than leading CIGS technologies and even more so than silicon-based PV. The researchers though, anticipate that with further research they should be able to create CTZS PV cell on par with CIGS cells.