Neither Sphere nor Cube - Analyzing the Particle Shape Using Small-Angle Scattering and the Superball Model

Accurate characterization of the nanocrystal shape with high statistical relevance is essential for exploiting the strongly shape-dependent properties of cuboidal nanoparticles towards applications. This work presents the development of a new small-angle scattering form factor based on the superball geometry. The superball quantifies the characteristic rounding of corners and edges of cuboidalnanoparticles with a single parameter. Applied to small-angle scattering data of sufficiently monodisperse nanoparticles, the superball form factor enables differentiation between the effects of extendedparticle size distribution and irregular particle shape. The quantitative application of the superball form factor is validated against microscopy data for a series of monodisperse nanoparticles and implemented into the user-friendly, open source software Sasview.