Chemistry in Pictures: Small, small walls

The tiny building blocks that form this crumbly wall are silver nanocubes just 75 nm tall. This raises the question, How did anyone stack these tiny, tiny cubes so cleanly? We have Harshal Agrawal and Erik Garnett to thank for that. The duo, a PhD researcher and a professor, respectively, at the University of Amsterdam, started by creating a sort of ink that consists of ethanol with nanocubes floating around inside it. After dropping the ink onto a surface, the researchers pressed it with a stamp patterned with nanosized trenches, which corralled the little cubes into the shape of trenches. Both the stackability of the cubes and fact that there’s very little space between them make them superior to nanospheres for constructing these kinds of structures. This technique is especially good for quickly making a lot of nanostructures out of small cubes that have uniform crystalline structures, such as an array of thin-walled rings (below), which might be useful for making solar cells.

Credit: Harshal Agrawal. Read the paper in ACS Nano (2020, DOI: 10.1021/acsnano.0c04793)

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