Environmental Leader

A new solar cell under development from IBM boasts an efficiency of 9.6 percent, which is 40 percent higher than previous incarnations.

IBM touts the new thin-film photovoltaic solar cell as a “world record” for its type.

The thin-film photovoltaic technology (see image) is comprised of copper, tin, zinc, sulfur and/or selenium, according to IBM’s Smarter Planet blog. Because these elements are earth-abundant, this type of solar cell could see wide production.

Other commercial thin-film solar cells have achieved 11 percent efficiency or more, but those incorporated costly compounds such as copper indium gallium selenide or cadmium telluride.

IBM chose to pursue a cell that used cheaper materials. The higher efficiency relates to the quality of the absorber layers achieved in the reported devices, said David Mitzi, Manager, Photovoltaic Science and Technology, IBM Research.

“One potential impact on the film quality relates to the solvent we are using,” Mitzi said. “Hydrazine is able to stabilize metal chalcogenide anions in solution.”

Because hydrazine is weakly coordinating and decomposes readily into nitrogen, hydrogen and ammonia, there are no impurities (e.g., oxygen, carbon or chlorine) left in the film that can impede the performance of the device, he said.

So far, the new thin-film solar has not been demonstrated in live situations, said Mitzi, team leader of the IBM Research group that developed the cell.

“This is a very young project, at less than nine months, and is still at a very early stage of development.”

IBM says it does not intend to manufacture the solar cells, but will instead license the technology.