For years, perovskites have been hailed as the “holy grail” of solar energy thanks to their promise of highly efficient and cheaper solar cells. Perovskites are a class of materials with similar crystalline structures with high superconductivity, high magnetoresistance, and high ferroelectricity, making them a potential replacement for silicon. Perovskite thin-film PV panels can absorb light from a wider variety of wave-lengths, allowing them to reach efficiencies of around 40% compared to silicon’s theoretical limits around 30%. Unfortunately, perovskites are notoriously unstable and highly susceptible to degradation when exposed to common environmental factors.
But now researchers at the University of Cambridge have unveiled a new halide perovskite that’s much more stable than conventional perovskites by fine-tuning them at the atomic level, opening the door for more powerful, durable and efficient devices.
The researchers used a vapour-based technique to create two- and three-dimensional perovskites one layer at a time, enabling them to accurately determine the thicknesses of the perovskite films down to fractions of an atom. Indeed, the scientists are able to create perovskite layers on the Angstrom level–or a tenth of a nanometer. They then meticulously stack these layers atop each other in a way that their atoms align perfectly, allowing their electrons and holes (the electrons’ positively charged opposites) to move freely in a process similar to the one used to make commercial semiconductors.
In effect, the layers act like one-way streets that guide charges and prevent them from wasting energy as heat. The researchers have achieved energy difference between the layers exceeding half an electron volt and extended the lifetime of electrons and holes to more than 10 microseconds, much longer than usual.
Related: Christmas Day Gasoline Prices Set To Fall To Covid-Era Levels
“Changing the composition and performance of perovskites at will – and probing these changes – is a real achievement and reflects the amount of time and investment we’ve made here at Cambridge,” said Professor Sam Stranks, who co-led the research. “But more importantly, it shows how we can make working semiconductors from perovskites, which could one day revolutionize how we make cheap electronics and solar cells.”
Perovskite technology has been advancing at a rapid pace. In 2012, scientists finally succeeded in manufacturing thin-film perovskite solar cells, which achieved efficiencies over 10%. But since then, eff