Superthin Gallium Arsenide solar power could displace silicon solar power as installation costs stay stubbornly high

The world has the capacity to manufacture over 40 Gigawatts of solar panels each year, the vast majority of them silicon-based. And it’s easy to see why: our expertise with processing the material has led to a staggering drop in costs, making photovoltaics (PVs) much more cost-competitive than just about anyone had predicted.

But that manufacturing innovation hasn’t been matched on the basic research side; it’s been over a decade since the last time anyone set a new efficiency record for silicon cells. And, even as manufacturing costs have dropped, the cost of support equipment and installation has remained stubbornly high and is an ever-increasing slice of the total price of PV systems.

Teams have figured out how to make extremely thin layers of GaAs. Harry Atwater’s group at Caltech has developed a process that allows them to peel hundreds of thin layers off a large aggregate of the material, much like individual graphene sheets can be peeled off a block of graphite. The end result is an extremely thin film of GaAs (he passed some samples around to the audience).

John Rodgers, who works at the University of Illinois at Urbana-Champaign, grows thin layers of GaAs separated by a thin sacrificial layer. When the sacrificial layer is etched away, you’re left with a collection of thin GaAs chips; the silicon wafer they were grown on can then be recycled, cutting down on the costs significantly. A plastic stamp can then pick up the chips and “print” them onto just about any surface, including one pre-patterned with wiring.

Both Rodgers and Atwater have started companies to try to commercialize their work, and the devices they’re making are already above the 40-percent efficiency mark—double that of silicon cells. Rodgers’ company already has a 5MW capacity plant, and he said that scaling up production to an 80MW capacity plant would let them produce devices that are cost-competitive with coal.

Without a breakthrough in installation costs then it will make sense to use the double efficiency of gallium arsenide.

SOURCE – Arstechnica

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