Promising discovery could lead to a better, cheaper perovskite solar cell (Nanowerk News) McGill University researchers have gained tantalizing new insights into the properties of perovskites, one of the world's most promising materials in the quest to produce a more efficient, robust and cheaper solar cell.

In a study published in Nature Communications ("Two-dimensional electronic spectroscopy reveals liquid-like lineshape dynamics in CsPbI 3 perovskite nanocrystals"), the researchers used a multi-dimensional electronic spectrometer (MDES) - a unique instrument hand-built at McGill - to observe the behaviour of electrons in cesium lead iodide perovskite nanocrystals.

The MDES that made these observations possible is capable of measuring the behaviour of electrons over extraordinarily short periods of time - down to 10 femtoseconds, or 10 millionths of a billionth of a second. Perovskites are seemingly solid crystals that first drew attention in 2014 for their unusual promise in future solar cells that might be cheaper or more defect tolerant.

"It's the most exciting result that I have been a part of since starting in science in 1995," said senior author and McGill chemistry professor Patanjali Kambhampati of the discovery of perovskite's liquid-solid duality. "Instead of searching for perfection in defect-free silicon microelectronics, here we have a defective thing that's defect-tolerant. And now we know a bit more about why that is."

As the researchers looked more closely at the crystals using the MDES, what they saw was something that challenges our conventional understanding of the difference between liquids and solids.