The University of Sydney team has achieved a record 23.3% efficiency for a 16 cm² triple-junction perovskite–silicon cell
The smaller 1 cm² version reached 27.06% efficiency and passed rigorous IEC thermal cycling tests
Stability and performance gains came from redesigned perovskite chemistry, gold nanoparticle connectors, and improved surface treatments
A University of Sydney research team claims to have set a world record for developing the ‘largest’ and the ‘most efficient’ triple-junction perovskite-silicon tandem solar cell. The team reported achieving an efficiency of 23.3% for a 16 cm² device, with an open circuit voltage of 3.16 V, while reaching 27.06% for a smaller 1 cm² cell, setting ‘new standards’ for thermal stability.
The 1 cm² solar cell passed a standard International Electrotechnical Commission (IEC) test that subjected it to 200 cycles of extreme temperatures, from -40°C to 85°C, which the team calls a ‘global first’. It retained 95% of its efficiency even after more than 400 hours of continuous exposure to light.
“This is the largest triple-junction perovskite device yet demonstrated and it has been rigorously tested and certified by independent laboratories. That gives us further confidence that the technology can be scaled for practical use,” said Professor Anita Ho-Baillie, who is also the research lead and John Hooke Chair of Nanoscience at the University of Sydney Nano Institute and School of Physics.
Ho-Baillie’s team attributes the success of its research to the re-engineering of perovskite material chemistry and the triple-junction cell design. The team replaced methylammonium, which is less stable but commonly used in high-efficiency solar cells, with rubidium, creating a perovskite lattice that’s less prone to defects and degradation.
Additionally, piperazinium dichloride was used as a new surface treatment in place of less stable lithium fluoride.
Researchers linked the 2 perovskite layers using tiny gold nanoparticles. Using advanced electron microscopy, they found the gold forms separate nanoparticles, not a continuous film, and then adjusted their coverage to improve the solar cell’s light absorption and electricity flow.
Perovskites, a promising low-cost solar material, can capture more sunlight when combined with silicon. But scaling them up and keeping them stable outside the lab has remained a major hurdle.
With these developments, Ho-Baillie says the team was able to improve both the performance and the resilience of these solar cells over time and under stress, moving the technology closer to commercial use. The team worked in collaboration with international partners from China, Germany, and Slovenia, with support from the Australian Renewable Energy Agency (ARENA) and the Australian Research Council.
The research work, titled Tailoring nanoscale interfaces for perovskite–perovskite–silicon triple-junction solar cells, has been published in the journal Nature Nanotechnology.