Researchers at the University of Queensland say they have set a new efficiency record for a specific type of solar cell that is cheaper and quicker to make than conventional silicon-based cells.
The team, led by Professor Lianzhou Wang, have created a tin halide perovskite (THP) solar cell capable of converting sunlight to electricity at a certified record efficiency of 16.65 per cent.
The reading achieved by this lab was nearly one percentage point higher than the previous best for THP solar cells.
“It might not seem like much, but this is a giant leap in a field that is renowned for delicate and incremental progress,” Professor Wang said.
“The reading is in line with many silicon-based solar cells currently on the market but with the potential to be cheaper and quicker to make.
“We are thrilled with the record and also to be contributing to the progress of cost-effective renewable energy technology.”
This latest record comes five years after Wang’s lab, which works across UQ’s Australian Institute for Bioengineering and Nanotechnology and School of Chemical Engineering, set a benchmark for efficiency in solar cells using quantum dots.
Lead perovskite solar cells have shown promise in the lab, with a demonstrated 25.5 per cent efficiency, though they have a ceiling of 32 per cent.
And lead, being toxic, is an unpopular choice because of the risk of contamination in the local environment.
Tin halide perovskite is seen as the most promising alternative, with lower toxicity, and a theoretical efficiency of up to 33.4 per cent.
While the 16 per cent result is in line with the average polycrystalline silicon cell – which, like THP cells, are cheaper to manufacture than monocrystalline silicon cells – it falls short of the average efficiency of monocrystalline silicon cells, which generally sit at between 20 to 23 per cent, and which make up a huge share of the market – in 2023, 98 per cent of global PV shipments were monocrystalline.
Research group member Dr Dongxu He said many of the methods, processes and materials used to set the quantum dot record in 2020 inspired the lab’s efforts to improve the performance of the THP cells.
“There is great commercial potential in THP solar cells because perovskite devices are more sustainable to produce than silicon-based solar cells,” he said.
“The benefit of THP’s is that we’re dealing with more eco-friendly tin and not the toxic lead that is widely used in most of the perovskite solar cells, meaning they can be safely installed around the home.”
The use of tin precursor had previously been problematic because of the sub-standard quality of the fast-crystalline thin films used in manufacturing THP solar cells, leading to a dip in efficiency.
Dr Peng Chen said the group overcame this hurdle by incorporating caesium ions to improve the microstructure and reduce defects in the THP film.
“This is what allowed us to reach a record level of efficiency while still having a product that would pass stringent environmental checks,” Dr Chen said. “I think we have a formula now that will only keep improving.”
