Influence of sintering necks on the spectral behaviour of ITO clusters using the Discrete Dipole Approximation

•We investigate the necking phenomenon in ITO fractal-like aggregates.•Extinction diagrams are sensitive to changes of the neck size.•We propose a simple procedure for measuring the neck size in ITO aggregates.

In this paper we study the spectral behaviour of indium tin oxide (ITO) nanoparticle clusters using different sinter neck models for the connections between the primary particles. The investigations include light scattering calculations based on the Discrete Dipole Approximation (DDA). The corresponding clusters are generated using the Cluster-Cluster algorithm proposed by Filippov et al. Different sintering neck models led to significantly different spectral features. A spectral neck factor that reveals the thickness of the necks connecting the primary particles with a simple measurement method is introduced.