Next-gen solar

Scientia Professor Xiaojing Hao led the UNSW research team, which set a new benchmark for 676cm² perovskite solar submodules.

The researchers say the world record demonstrates that perovskite solar technology can maintain high efficiency across much larger areas than laboratory-scale cells, highlighting its potential for scalable manufacturing and widespread use in photovoltaic (PV) modules.

Perovskite is a potentially important next-generation solar material because of its ability to convert sunlight into electricity with very high efficiency, while also offering the prospect of low-cost manufacturing.

The team achieved a certified stabilised power conversion efficiency of 23.5%, beating the previous benchmark by 0.6 percentage points. It is also an important achievement because it sets an efficiency benchmark for a 30 x 30cm perovskite submodule, with an aperture area of 676cm², further narrowing the efficiency gap with small-area laboratory cells, which are typically only around 1cm².

Prof. Hao says it’s not just about setting another efficiency record.

“It is about developing materials and device concepts that continue to perform when they are translated from laboratory cells to industrially relevant areas,” she says.

“Materials that work exceptionally well in a small laboratory device do not necessarily behave in the same way under scaled-up processing conditions.

“Our focus is therefore not simply on finding high-performance materials, but on understanding how to design materials and interfaces that remain effective under the conditions required for large-area fabrication.”

Perovskite can be combined with traditional silicon cells in a so-called tandem solar cell, since the two materials can capture different parts of the solar spectrum and therefore work well together to turn more of the sunlight into electricity.

It is expected perovskite will be used increasingly as an additional layer on top of existing silicon solar cells, potentially allowing manufacturers to boost the output of solar modules without proportionately increasing their size.

However, it is not yet ideal for widespread PV use because it can degrade when exposed to moisture, heat and prolonged sunlight; making long-term stability, durability and reliable large-scale manufacturing major challenges.

According to UNSW, larger perovskite modules require precise control over film uniformity, crystallisation, defects, interfaces and electrical interconnection across a substantially greater area – which means scaling them up from small lab samples can also be problematic.

“Achieving high efficiency at this scale requires much more than simply transferring a laboratory process to a larger substrate,” says Prof. Hao.

“This partnership between UNSW and UtmoLight is very significant because it has allowed us to test and adjust our ideas at the very start of the process.

“We have been able to test our ideas to check if they can be upscaled, which means that we are not wasting our time on things that aren’t feasible.

“This is also good for industry … because they get to know whether there are innovations that can help them overcome some limitations in their large-scale processing systems.”

The researchers now hope to be able to scale up the efficiency testing even more in the next few months by producing a full-scale module with a 2.8m² area, representative of full-scale commercial PV module dimensions, to further validate their work.

They aim to achieve around 18–19% efficiency for the larger solar module, but acknowledge that further work is needed to improve efficiency, reproducibility and long-term stability before the technology can be widely deployed.

Photos courtesy of UNSW Sydney.

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