In grad school I studied nanocrystals, little tiny things a few nanometers in size (ten thousand times smaller than a human hair). I was working with @MDrndic who now does a lot of bio-nanoscience too, but when I started we were all focused on nanoelectronics.
There are a ton of cool things about nanomaterials, but what really drew me in is that the laws of physics are fundamentally different at the nanoscale. It's like a crazy sci-fi world that underlies our own!
I did my thesis looking at a type of nanocrystal that can generate current from light, for solar cells, LEDs, etc. What colour light they produce or respond to depends on their size, so each of these vials has a different size nanocrystal of the same material: 
Each colour of light has a different energy associated with it, and it's more like an atomic property to be so sensitive to different energy levels. This is why nanocrystals are sometimes called 'artificial atoms'!
Nanomaterials are kind of in between the laws of physics at the macroscale world we live in, and the laws of physics for the smallest objects like electrons, quarks, etc. They're a way for scientists to probe the quantum world.
But you need a lot of fancy tools to study nanoscience, powerful microscopes and sensitive electronic equipment! So I came to Ireland to work @cranntcd and later @ambercentre in the @BolandLab, because they had great resources and collaborations for #nanoscience.
