The material, Apex Flex, can be used for a tandem design that is flexible and stable enough for car-top application at a cost 200 times less than flexible PV technologies of similar specific power.
“The demonstration of high specific power, flexible PV, with the cost and throughput of solution processes, is a great outcome,” said David Moore, NREL scientist and co-creator of Apex Flex.
The key was the development of a wide-bandgap perovskite layer containing dimethylammonium that was able to withstand heat, light, and operational tests, while providing a reliable and high voltage. Previous versions were unstable, so the team used atomic layer deposition (ALD) to tune the material for a tandem cell.
Between the two perovskite materials, NREL’s team developed a recombination layer that eliminates shunt paths and is around 80% thinner than previous technologies.
“Pairing more than one metal halide perovskite absorber in a single solar cell enables a truly differentiated solar technology that is high-efficiency, low-cost, and lightweight,” said fellow co-creator and NREL scientist Axel Palmstrom. “This collaborative effort has brought all-perovskite tandems closer to commercial reality, and we are excited to see their real-world applications in the near future.”
The Apex Flex continuously adjustable bandgap cell has a potential efficiency of 37 percent, and the highest reported efficiency for thin film at 24.5%. Apex Flex can be manufactured with high-speed, roll-to-roll methods.
Apex Flex has resulted in two patent applications that were licensed for commercialization by Swift Solar.
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