Conversion efficiency gains are widely accepted to be one of the key ways in which PV manufacturers and developers can bring down the cost per watt of PV. Gains in CIGS thin film development have continued, not only potentially delivering cost per watt gains but also closing the gap between CIGS’ efficiencies and those of crystalline silicon manufacturers.
The latest efficiency record to be announced has been achieved by the ZSW, with a 20.8% CIGS cell. Equipment supplier Manz, which is also located in the Baden-Württemberg region in Germany’s south, has secured the exclusive rights to the technology. Manz and ZSW share a long history of collaboration and the equipment company will attempt to transfer the efficiency gains achieved in the ZSW labs to scale production at its CIGS innovation line, formerly that of Würth Solar.
ZSW and Manz manufactured the record-holding cell using a co-evaporation deposition technique on a glass substrate, a technology the two partners developed further and jointly patented.
ZSW and Manz are not the only groups to be making progress with CIGS technology. Switzerland’s Federal Laboratory for Materials Science and Technology (EMPA) achieved the next highest efficiency result for CIGS with a result of 20.4%, announced in January. EMPA deposits its CIGS layer onto a flexible substrate. The EMPA CIGS cell is only centimeters in size.
The world’s largest CIGS producer is Japan’s Solar Frontier and it announced, also in January, a CIGS cell efficiency result of 19.7%. The Solar Frontier cell was cut from a 30 cm x 30 cm glass substrate and the company claimed its result was achieved using a sputtering and selenization process similar to those used in its scale production.
This most recent technological milestone, achieved by ZSW and Manz, will make the value proposition of CIGS thin film even more compelling, according to Manz CEO Dieter Manz. "CIGS thin-film is more efficient than polycrystalline," said Manz. "I am greatly pleased that we played a major role in achieving this."
As the holder of the exclusive rights to the ZSW technology, Manz says it will give Manz CIGSfab customers considerable cost per watt advantages. Manz previously produced a champion module with an efficiency of 14.6%, which it says rivals polycrystalline modules.
In a statement announcing the exclusive rights deal, Dieter Manz added that its CIGSfab, which is a turnkey solution, is particularly suitable for emerging PV markets. Local production can be scaled as needed, and products can meet local content provisions and also source raw materials locally, said Manz.
"Thanks to the high level of integration compared to crystalline production, the production process is much more simple, considerably more affordable and can thus be realized much faster."
Emerging markets such as the Middle East or South Africa could be regions well suited to Manz CIGSfab production. CIGS technology also has, in general, a superior temperature coefficient than crystalline technologies, making it well suited to hotter climates.
The December edition of pv magazine will feature an article about thin film technology and production techniques.