3 Results and Discussions Figure shows a TEM micrograph of the FATO NPs with the corresponding particle size distribution measured on 120 particles as well as the particle size distribution as measured by dynamic light scattering after deagglomeration with a Hielscher 400S ultrasonic probe. The TEM image implies a particle size with a median value of 7.7 nm whereas the DLS measurement shows a median size of 42 nm, due to its sensitivity towards agglomeration.