Australian solar team beats perovskite efficiency milestone, joins elite global club

Australian scientists have joined an elite club of just eight around the world, making a perovskite solar cell that can hit 30 per cent efficiency. 

Led by storied University of Sydney professor Anita Ho-Baillie, the Sydney team’s work was weighed and measured by the US National Renewable Energy Laboratory (NREL). 

“It shows that we are capable of producing high performance cells. The next step we will achieve is higher performance, either by double junction or triple junction,” Ho-Baillie says. 

“Triple junction has a theoretical efficiency of around 50 per cent. And we’re also working on  making sure the perovskite lasts as long as silicon cells.”

The Sydney researchers built a monolithic perovskite-Si tandem solar cell which swapped out lithium-iron for morpholinium bromide (MLBr) as the perovskite material. 

They coated the silicon panel with perovskite, to make a double junction cell – that is, when another light absorbent material is stacked on top of the silicon. 

“We directly fabricate that onto the silicon,” Ho-Baillie says. 

“Double junction has a theoretical limit of around 40 per cent so we’ve still got a good way to go but the NREL result is a very good milestone.”

Only eight other groups around the world have beaten the 30 per cent threshold in the NREL lab.  

It’s an involved exercise because teams must have a cell they’re confident of in their own labs and which is stable enough to survive the journey to the US and to wait around until it’s their turn under the testing machine. 

Ho-Baillie’s team is working with SunDrive to create a cell that can be easily replicated in a commercial manufacturing facility. This means designing a cell that can be warranted for at least 15 years and works for 25 years, but is also relatively simple to make. This is why they used a thin coating of perovskite material over the silicon.

Her team was awarded a $2.5 million grant in 2020 to improve the efficiency and durability of silicon-perovskite photovoltaic cell technologies, just after Ho-Baillie’s group achieved a key durability milestone for silicon-perovskite.

Race to make perovskites work

A number of teams in Australia are working on improving different elements of perovskite cells. 

RMIT scientists are working on testing processes, and a pre-revenue startup in California called Caelux is looking hard at University of New South Wales research that simplifies how the performance of individual perovskite solar cells are tested. It’s an area that RMIT is also looking into.

Western Australian graphene supplier First Graphene, Halocell Energy, and Queensland University of Technology (QUT) won $2 million in funding from the Australian government last year to commercialise ultra low-cost and flexible perovskite solar cell fabrication techniques, using Halocell’s roll-to-roll (R2R) production process at its Wagga Wagga plant.

Overseas, Microquanta, GCL Perovskite, Utmolight, and Oxford PV have commissioned 100 megawatts (MW) of pilot manufacturing lines for perovskite cells, to be operational by 2030. 

In February, Oxford PV said it achieved 25 per cent efficiency with a large panel, a feat in itself as perovskite technology has historically worked well in small sizes but struggled to scale up.