Paul van Gerven
8 July

Swiss scientists have pushed through the 30-percent efficiency barrier with tandem silicon-perovskite solar cells. The new records takes the technology beyond silicon’s theoretical upper limit of 29.4 percent. With current top efficiencies slightly below 27 percent for all-silicon cells, there isn’t much room left to improve upon.

Researchers at EPFL and ECSM came up with two separate designs that break the 30 percent barrier. For the first, they adapted materials and fabrication techniques to deposit high-quality perovskite layers from solution on a planarized silicon surface, reaching a power conversion efficiency of 30.93 percent for a 1 cm2 solar cell. For the second, they used a new version of a hybrid vapor/solution processing technique compatible with textured silicon surfaces, they have produced a solar cell with a power conversion efficiency of 31.25 percent (again on 1 cm2).

perovskite
Credit: Christian Wolff (EPFL)

“Tandem perovskite-on-silicon technologies have been said to have the potential to exceed the 30-percent efficiency benchmark, but this is the first time this long-predicted potential has been demonstrated, which should hopefully pave the way for even cheaper sustainable electricity in the future,” said Christian Wolff of EPFL.

“These high-efficiency results will now require further R&D to allow their scaling up onto larger surface areas and to ensure that these new cells can maintain a stable power output on our rooftops and elsewhere over a standard lifetime,” added Quentin Jeangros of CSEM.