First Principles Calculations of the Stability of CdSe Nanoparticle Superlattices*

The periodic superlattice structure and the collective physical behavior of semiconductor nanoparticle (NP) solids are largely governed by the ground-state dipole moment¹and polarizability of the NPs forming the lattice. We used plane wave Density Functional Theory (DFT) and the Qbox code² to compute dipole moment and polarizability of CdSe clusters of different sizes³ and study the effect of NP interaction on these fundamental properties. We then used our results to derive an analytical model of the dipole moment and polarizability as a function of cluster distance. We employed our model to investigate the energy and stability of clusters in different superlattice structures.

[1] Talapin DV, Shevchenko EV, Murray CB, Titov AV, Kral P. Dipole-dipole interactions in nanoparticle superlattices. Nano Lett. (2007);7(5):1213–1219.
[2] www.qboxcode.org
[3] Vörös M, Galli G, Zimanyi GT, Colloidal Nanoparticles for Intermediate Band Solar Cells. ACS Nano (2015), 9, 6882−6890.