While around 90% of solar panels currently on the market are made out of silicon, adding a new material may soon make existing module design even more efficient.
Perovskites are a cheap class of materials that can easily be combined with silicon for more efficient electricity generation. Perovskite cells have come a long way since 2009, when they boasted an efficiency of just 3.8% for a few minutes. The most advanced perovskite cells “now boast an efficiency of 22.7% and routinely work for thousands of hours under harsh test conditions,” according to recently published research.
The most recent breakthrough stems from a new method of combining the silicon-based and perovskite cells. Silicon-based cells have a surface made up of microscopic pyramids, which has historically made placing a homogeneous perovskite sheet on top difficult.
According to Swiss Researcher Florent Sahli, “Until now, the standard approach for making a perovskite/silicon tandem cell was to level off the pyramids of the silicon cell, which decreased its optical properties and therefore its performance, before depositing the perovskite cell on top of it. It also added steps to the manufacturing process.”
Sahli and his team’s new process uses evaporation technology to create an inorganic substance that surrounds the pyramids and allows for an easier placement of the perovskite layer. While the technology is not yet commercially available, it is currently undergoing tests to increase efficiency as well as the long-term stability of the perovskite film.
Perovskite and Silicon Tandem Cells: A Perfect Pairing
Like silicon solar cells, modules made solely out of perovskite are possible. However, researchers have begun focusing on “tandem solar cells,” which feature a thin layer of perovskite cells - about one micrometer thick - on top of a layer of silicon-based cells.
While silicon is best at converting red and infrared light into electricity, perovskite is more efficient with green and blue lights. The resulting combination recently reached a record efficiency of 25.2%. However, researchers believe that efficiencies beyond 30% are possible in the near future.
(Pictured: Tandem Cell Model from source)
This new research comes at a critical moment for technology in the solar industry. Advancements are continuously being made to boost efficiency and reduce prices, but many believe that silicon solar cell technology is starting to flatline after decades of success.
While challenged, the widely recognized theoretical maximum efficiency for silicon-based solar cells is 29.4%. As researchers draw nearer to this limit, tandem solar cells offer the realistic possibility of exceeding this cap. According to the Swiss research team, integrating perovskite cells on top of silicon-based cells “would only add a few extra steps to the current silicon-cell production process, and the cost would be reasonable.”
Better yet, the materials needed to create perovskite cells are relatively abundant. Tandem solar cells and their potential hold certainly offer a lot to get excited about!
Should you wait for tandem cells to go solar?
Although the potential for perovskite-silicon cells are great, consider going solar soon to maximize your savings on your electricity costs. It will likely still be a few years before tandem cells are commercially available at a wide scale.
What's more, unless you have extremely limited roof space to place solar panels, the efficiency of standard solar panels are already at a high enough level to cost-effectively install an array.
To learn more about your home on solar, use our calculator to get an instant snapshot of what solar would look like for your home.