Perovskites have stolen center stage in the realm of photovoltaic technology and research, praised for their ability to bump up the efficiency of a typical solar array and for their relative affordability to traditional silicon materials. There has been much exploration-- and promising results-- of layering a thin sheet of the crystal atop a standard silicon cell in a solar panel. Yet many are deterred by the material’s compromise in durability and stability, thus limiting its potential to be used in various formats.

Stanford University and Oxford University scientists may have an answer-- eliminating the silicon altogether, and doubling up on the perovskites. Their findings, published in the most recent issue of research journal Science, are based upon the construction of a purely-perovskite solar cell capable of reaching 20.3% efficiency, a rate competitive with silicon cell technology. In an industry in which most research is geared towards perovskite-gilded silicon cells, their discovery is catalyzing.

“The all-perovskite tandem cells we have demonstrated clearly outline a roadmap for thin-film solar cells to deliver over 30% efficiency,” remarked co-author Henry Snaith of Oxford University. “This is just the beginning.”

How is a crystal cheaper than silicon?

Perovskite crystal is made using tin, lead, bromine and other common elements that are printed on glass or even plastic at room temperature.Silicon is often faulted for being a finicky and pricy material to work with, with even minor flaws greatly impacting the efficiency of an entire array and resulting in interference in the conversion of solar radiation to electrical currents. Not only is the crystal cheap to manufacture, but its design allows defects without a reduction in electrical output-- two factors that already make the technology favorable for mass production.

According to those involved in its research, these “perovskite tandem cells” still require some tweaking before being pushed as an accessible option to a larger audience-- scientists hope to phase out lead and other toxic compounds from crystal production, strengthen the construction and durability of the cell, and push for higher rates of efficiency.

Image from Phys.org, credit Dennis Schroeder / NREL