Artists Impression Perovskite Nanocrystals

Scientific instrument made at McGill reveals liquid-like properties of a stable substance.

McGill College researchers have gained tantalizing new insights into the properties of perovskites, one of many world’s most promising supplies within the quest to produce a extra environment friendly, strong and cheaper photo voltaic cell.

In a examine revealed in Nature Communications on October 31, 2019, the researchers used a multi-dimensional digital spectrometer (MDES) – a distinctive instrument hand-built at McGill – to observe the habits of electrons in cesium lead iodide perovskite nanocrystals. The MDES that made these observations doable is able to measuring the habits of electrons over terribly quick durations of time – down to 10 femtoseconds, or 10 millionths of a billionth of a second. Perovskites are seemingly stable crystals that first drew consideration in 2014 for his or her uncommon promise in future photo voltaic cells that is likely to be cheaper or extra defect tolerant.

A most enjoyable discovery

“It’s the most exciting result that I have been a part of since starting in science in 1995,” mentioned senior creator and McGill chemistry professor Patanjali Kambhampati of the invention 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.”

Solids appearing like liquids

Because the researchers appeared extra intently on the crystals utilizing the MDES, what they noticed was one thing that challenges our typical understanding of the distinction between liquids and solids.

“Since childhood we have learned to discern solids from liquids based on intuition: we know solids have a fixed shape, whereas liquids take the shape of their container,” mentioned Hélène Seiler, lead creator of the analysis and a former PhD scholar within the Division of Chemistry at McGill who’s at the moment on the Division of Bodily Chemistry, Fritz-Haber-Institut on the Max-Planck Institute. “But when we look at what the electrons in this material are actually doing in response to light, we see that they behave like they typically do in a liquid. Clearly, they are not in a liquid – they are in a crystal – but their response to light is really liquid-like. The main difference between a solid and a liquid is that a liquid has atoms or molecules dancing about, whereas a solid has the atoms or molecules is more fixed in space as on a grid.”

To learn: “Two-dimensional electronic spectroscopy reveals liquid-like lineshape dynamics in CsPbI3 perovskite nanocrystals” by Hélène Seiler et al in Nature Communications:

The analysis was funded by: Pure Sciences and Engineering Analysis Council of Canada (NSREC), Canada Basis for Innovation (CFI), Swiss Nationwide Science Basis, Fonds de Recherche du Québec – Nature et applied sciences (FQRNT)



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