Solar Frontier achieves record 20.9% cell efficiency on thin-film CIS

Solar Frontier, Japanese thin-film PV manufacturer has announced a new world record efficiency of 20.9% on copper, indium, selenium (CIS) cell, besting the previous world record of 20.8% for thin-film PV as well as the company’s own previous record of 19.7%.

This is the fruition of a combined R&D effort with Japan’s New Energy and Industrial Technology Development Organization (NEDO). The record efficiency was achieved on a small area cell (0.5 cm2) and has been independently verified by the Fraunhofer Institute (Germany).

The innovation that resulted in the record efficiency was the development of a hybrid method that combines 2 CIS cell production processes that are typically done separately: (a) deposition of copper, indium and selenium-based films, (b) a high-temperature reaction (called selenization) to carefully fuse the separate layers to produce a working semiconductor. Solar Frontier hopes its new hybrid high-temperature sputtering-selenisation process will overtake the conventional and more expensive co-evaporation process typically used to make CIS cells.

Although the resulting device area is small, Solar Frontier claims the technique used is compatible with its commercial CIS thin-film manufacturing operations. Satoru Kuriyagawa, CTO of Solar Frontier, says, “Solar Frontier’s new 20.9% efficiency record resulted from a CIS cell cut from a 30cm x 30cm substrate” produced using “the same method we use in our factories.”

Solar Frontier, the world’s second largest thin-film module manufacturer, is also banking on the advantages of CIS thin-film technology, which has seen significant advances of late. CIS is proving to be an attractive alternative to the Cadmium telluride (CdTe) technology championed by thin-film PV market leader, First Solar. In fact, the 20.9% record efficiency achieved by Solar Frontier for CIS technology is slightly higher than First Solar’s recent 20.4% record efficiency for CdTe.

In addition to being free of heavy metals like cadmium, Solar Frontier claims its CIS modules are also able to generate more energy per kW of installed PV (kWh/kWp) than crystalline silicon modules under real operating conditions.

Solar Frontier seems confident CIS technology will one day reach past the 25% efficiency mark, with Kuriyagwa claiming that CIS technology is capable of reaching efficiencies of up to 29.7%.

Whether such high efficiencies translate well from research cells into commercial modules remains to be seen, but Kuriyagwa seems confident this latest record will be significant for Solar Frontier. “The significance is two-fold”, he says, “It ensures we can transfer our latest achievement into mass production faster; and it proves the long-term conversion efficiency potential of [our] proprietary CIS technology.”

Top Image Credit: Solar Frontier

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Nitin Nampalli

Nitin is a regular contributor to Solar Choice News with a focus on solar PV technology. He holds a Master of Engineering Science in Renewable Energy from UNSW and a Bachelor of Science degree in Microelectronic Engineering from Rochester Institute of Technology, New York. He is currently a PhD candidate researching solar photovoltaics at UNSW. In addition to his studies, he has also worked extensively in solar PV research.
Nitin Nampalli