Swift Solar is betting perovskite can loosen China's grip on the solar supply

On the surface, perovskite solar cells seem ideal: they’re lightweight, more efficient than traditional solar cells, and cheap to produce.  

But the technology has struggled to achieve commercial viability, in part due to the panels’ short lifespan. 

• The top line: Though there’s still a long way to go, tandem perovskite panels — a more advanced technology geared at combating efficiency problems — are one step closer to commercialization with the close of Swift Solar’s $27 million Series A financing round. The Silicon Valley startup, which is preparing to break ground on its first factory, aims to use the money to reshore solar production and to bring their tandem panels to market. 
• The market grounding: Traditional silicon-based PV cells have limited light-to-power conversion efficiency that generally tops out around 20%, depending on conditions. Tandem perovskite cells, on the other hand, can exceed 30% efficiency, meaning that they have the potential to produce  more electricity for cheaper. Still, perovskite panels are unproven at scale — the compounds used to produce them lack durability. 

Tandem perovskite panels sandwich metal halide perovskites with silicon to create a hybrid cell that can soak up more of the solar spectrum and convert it to usable energy. The crystalline structure absorbs sunlight much more easily than silicon alone and lets loose more electrons to flow directly to the conductor and produce electricity more efficiently. 

Key to Swift’s pitch is the fact that perovskite panels require fewer materials than traditional panels, which could hypothetically help reshore production. Swift says that the perovskite solar supply chain could be based entirely within the United States and its allies — a stark contrast to China’s booming presence in silicon PV production. That is a particularly strong sell in light of new tariffs on Chinese cleantech imports.

However, perovskite is much more sensitive to the elements than silicon, which means panels have lifespans that can range from mere hours to several months. The compounds can disintegrate in water, degrade in the heat, and are particularly vulnerable to prolonged light exposure and oxygen, which pose potential problems for their use in energy production. 

According to the Department of Energy, “for mainstream solar power generation, technologies that cannot operate for more than two decades are unlikely to succeed, regardless of other benefits.”

Swift’s big bet

Tandem projects, however, can be more durable and may be closer to reaching commercialization. The DOE recently poured $44 million dollars into perovskite solar research and development; $7 million of the funding went to Swift Solar, which has received over $16 million total in federal and state grants. 

The company also recently secured $27 million in private funding at the close of its Series A round, which was co-led by Eni Next and Fontinalis Partners. Other new and existing investors include Stanford University, Good Growth Capital, and BlueScopeX. 

According to Swift, perovskite panels could decrease the cost of solar energy by up to 30% due to the performance gains and cost reductions they enable. The higher efficiency panels could also enable EVs to gain 15-plus miles of range per day when charged from perovskite solar roofs, the company said. 

Swift has yet to break ground on its first manufacturing facility, slated to produce 100 megawatts of tandem panels every year, nor has it started independent IEC-type testing of its panels. (However, the company began its own independent testing at the Sandia National Lab's perovskite accelerator last year.)

Meanwhile, other solar manufacturers at home and abroad are also starting to enter the perovskite fray. Last year, the Arizona-based First Solar acquired Swedish perovskite startup Evolar; the company recently set a new solar efficiency benchmark for thin-film solar modules based on copper, indium, gallium and diselenide (CIGS) technology.

And later this year, perovskite panel leader Oxford PV — which is backed by Norwegian oil giant Equinor as part of its renewable portfolio buildout — is expected to deliver its first panels as it ramps up manufacturing at its Brandenburg, Germany factory.

Editor's note: This story was updated on June 17 to clarify that Swift has begun its own independent testing, though it hasn't started IEC-type testing of its panels.