University of Queensland research has identified why promising next-generation perovskite solar cells struggle outdoors, and how smarter materials design could dramatically extend their operating lifetimes.
Perovskite solar cells have captured global attention because they are cheap to make and highly efficient, but their real-world durability has remained a major obstacle to commercial use.
UQ’s Dr Julian Andrew Steele has revealed that a key problem lies not in sunlight itself, but in the constant warming and cooling that solar panels experience every day.
“Unlike traditional silicon solar cells, perovskite materials expand and contract dramatically as temperatures change, creating mechanical stress inside the device,” Dr Steele said.
“This stress builds up because the perovskite layer expands much more than the other layers in a solar cell, yet the perovskite materials is relatively stiff and prone to cracking.
“Over hundreds of day–night cycles, tiny cracks and defects form in the light-absorbing layer, slowly reducing performance and shortening the cell’s lifespan.”
The research shows that standard testing methods developed for silicon solar cells – which rely on steady heat and constant illumination – fail to capture this critical degradation pathway.
At the atomic level, Dr Steele linked this behaviour to something called lattice anharmonicity, which describes how atoms jiggle and carve out uneven shapes as they vibrate inside the crystal as it heats up.
These irregular atomic motions drive unusually large thermal expansion in perovskites, setting them apart from more rigid semiconductor materials.
Dr Steele said recognising the true cause of degradation is key to making perovskite solar cells last longer.
“Recognising the real underlying degradation mechanisms of next generation solar technologies will allow them to operate at impressive operating efficiencies for longer,” he said.
“At this stage, silicon solar has roughly a 30-year warranty, and new technologies like perovskites – which have only been in the wild for about 15 years – can hardly compare.
“Rather than seeing thermal expansion as an unavoidable flaw, my analysis outlines how it can be engineered by carefully choosing perovskite compositions and crystal phases that curb its impact.
“By connecting atomic-scale physics with real-world performance, this work helps provides a clearer pathway towards durable, commercially viable perovskite solar technologies.”
The research is published in Nature Energy.
