|Oct 31, 2019|
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 CsPbI3 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.|
|"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," said Hélène Seiler, lead author of the research and a former PhD student in the Department of Chemistry at McGill who is currently at the Department of Physical Chemistry, Fritz-Haber-Institut at 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."|
|Source: McGill University|
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