Several solar companies – including Hanwha Qcells, Trinasolar and LONGi – have recently announced breakthroughs in tandem solar cell technology, combining traditional silicon photovoltaic technology with perovskite to increase efficiency.
Perovskite is inexpensive compared to silicon, but has less stable chemistry, which has historically presented scalability and commercialization challenges. However, Qcells announced May 14 that its tandem solar cells have reached a key stability milestone, achieving “successful stress test validation for its tandem modules according to both [International Electrotechnical Commission] and [Underwriters Laboratories] certification standards.”
“These tests also complied with tandem-specific requirements for power measurements, making them a key first in the industry,” Qcells said. “The standard-compliant execution of the stress tests and measurements has been independently confirmed by TÜV Rheinland.”
A tandem solar cell uses stacked layers of different materials to capture a wider range of the solar spectrum, allowing modules to bypass the Shockley–Queisser limit, a theoretical limit which prevents cells that only use one material from absorbing any more than 30% of the solar energy that shines on them.
“The tested cells and modules are typical devices from our [research and development] pilot line in Germany and have been fabricated by exclusively using processes that are feasible for mass production,” said Fabian Fertig, head of tandem R&D at Qcells Germany, in a company release. “This result is laying the groundwork for future commercialization of this exciting technology.”
Qcells was founded in Germany and is headquartered in South Korea but has substantial investments in the U.S., including a panel manufacturing facility in Cartersville, Georgia.
Chinese company Trinasolar announced March 28 that it had developed the “world's first industrial-standard solar PV module delivering over 800W of maximum power,” in the form of perovskite/silicon tandem solar cells with an industrial standard size of 210mm and a peak power output of 808W.
This breakthrough is a “significant step toward the industrialization of tandem modules,” said Gao Jifan, Trinasolar’s Chairman and CEO.
On April 9, Trinasolar announced a deal with Oxford University spinoff Oxford PV, a solar company specializing in perovskite solar technology. The two companies reached an “exclusive patent licensing agreement for the manufacture and/or sale of perovskite-based photovoltaic products in China with an additional right to sublicense,” Oxford PV said in a release.
“This agreement is a milestone in our mission to make perovskite PV mainstream and affirms the pivotal role of patents in the photovoltaics of today and the future,” said David Ward, Oxford PV’s CEO. “We encourage other parties interested in a license outside of China to contact us.”
LONGi, another China-based company, announced a “two-terminal crystalline silicon-perovskite tandem solar cell that has achieved a conversion efficiency of 34.85%” on April 15, breaking a previous silicon-perovskite tandem cell efficiency record of 34.6%, which LONGi had also set. The result was certified by the U.S. National Renewable Energy Laboratory, the company said.
