Researchers from the Australian National University (ANU), in collaboration with researchers from and the California Institute of Technology, have developed a way to combine silicon with perovskites to achieve higher efficiencies and lower production costs. They believe that this could lead to cheaper and more efficient solar technology.

The new way to create crystalline silicon and perovskite tandem PV cells is claimed by the team to be the simplest method of doing so.

To combine two cells, engineers usually use an interlayer to allow electrical charge to be transferred easily between the two cells, so they can function in tandem.

co-author Daniel Jacobs from the ANU describes this process as similar to making a club sandwich with extra bread in the middle – it plays a structural role, but the sandwich would taste better without it. “We’ve found a new way to simply stack the two cells together so they’ll work efficiently with each other – we don’t need the interlayer, or extra bread, anymore,” Jacobs said. The team says this minimizes energy waste and simplifies the structure, making it potentially cheaper and easier to produce.

“With tandems it’s crucial to demonstrate a fabrication process that is as simple as possible, otherwise the additional complexity is not worthwhile from a cost perspective,” Jacobs said. “Our structure involves one less fabrication step, and has benefits for performance too.”

“We’ve already reached 24% improvement in efficiency with this new structure, and there’s plenty of room left to grow that figure,” Jacobs said.

The ANU-led study was funded by the an Australian Renewable Energy Agency (ARENA) grant, as part of a project in collaboration with UNSW and Monash University focused on tandem solar cell development methods.