ZSW sets new world record for thin-film solar cells

The Centre for Solar Energy and Hydrogen Research BadenWürttemberg (ZSW) has nudged up the performance bar for thinfilm solar cells yet another notch.

22.6 percent efficiency achieved for a CIGS solar cell.

The Stuttgart-based scientists achieved 22.6 percent efficiency with their latest advance, topping the performance of a Japanese-made cell by 0.3 percentage points and bringing the world record back home to ZSW for the fifth time.

And the pace of advances is picking up as recent strides in cell performance go to show: The efficiency of thin-film solar cells based on copper indium gallium iselenide (CIGS) has increased more in the last 3 years than in the previous 15. As efficiency goes up, the cost of solar power comes down. The researchers in southwestern Germany are sprinting from one success to the next. It was just three months ago that the team achieved 22.0 percent efficiency with a cell that outperformed everything the scientists had developed to date, setting a European record in the process. The cell that upped this mark another 0.6 percentage points was made in a state-of-the-art laboratory coating plant using the coevaporation method. The Fraunhofer Institute for Solar Energy Systems ISE has confirmed the results.

ZSW’s record-setting cell has an area of about 0.5 cm², a standard size for test cells. The institute’s researchers accomplished this latest performance boost by improving the manufacturing process at several points, one being the post-deposition treatment of the CIGS surface with alkaline metal compounds being incorporated into this layer.