@Tyberius I am not 100% sure about this, but aren't the unit cells for bulk and nano materials of a particular system same? Furthermore although I originally picked the particular cif file from a paper which had looked at bulk structures but when I look at another paper which actually looks at the nano structures of the said material they also have the same unit cell(https://pubs.acs.org/doi/10.1021/jacs.0c04919)!

Furthermore, do you think that making this a circular quantum dot instead of a rectangular one could help us ??