Calculation of the electronic and optical properties of colloidal nanostructures using the comprehensive method based on atomic effective pseudopotentials

Abstract

The quantum mechanical treatment of the electronic properties of colloidal semiconductor nanostructures, as used in experimental settings, remains a challenging task till today. Colloidal nanocrystals such as quantum dots or quantum wires with less than a thousand atoms are rarely synthesised and investigated experimentally, but that is the maximum size which can be treated by standard ab initio methods with a reasonable amount of computational resources, despite a great step forward in the parallel computing during the last decade. However, the theoretical understanding of the experimentally observed phenomena is of utmost importance. In this work a new comprehensive theoretical method is presented, which requires very moderate computational resources, but provides accurate ab initio results for the whole experimental range of sizes (from hundreds to more than 100 000 atoms) and dimensions (nanoplatelets, quantum wires, and quantum dots) of the colloidal nanostructures. The method allows a direct comparison between calculated and experimentally measured electronic and optical properties by including the effect of atomistic surface passivation and the influence of surrounding medium via a dielectric screening function.