Tailoring on the nanoscale: Control over size, shape, composition and self-assembly of copper chalcogenide nanocrystals

Abstract

Semiconductor materials are commonplace in everyday life and most people could not live without them. Recently, colloidal semiconductor nanocrystals have gained a lot of interest, due to the possibility to precisely tune their optoelectronic properties by tuning the size and shape of the nanocrystals. Nowadays, such colloidal semiconductor nanocrystals show potential use in applications such as television screens, solar cells and light-emitting diodes (LEDs). However, the integration of semiconductor nanocrystals into devices is severely hindered by toxicity issues concerning the use of heavy metals such as Cd and Pb. Copper chalcogenide nanomaterials offer an interesting alternative, since they have shown to possess similar (e.g. photoluminescence), or novel (e.g. plasmonics), properties and are comprised of less toxic and more abundant elements such as Cu, Zn and Sn. Although a lot of research has been performed to obtain the same level of mastery over the synthesis of Cu-chalcogenide nanocrystals, as is currently available for Cd- and Pb-chalcogenide nanocrystals, and hence precisely tune the optoelectronic properties of colloidal Cu chalcogenide nanomaterials, there is still room for improvement. In this thesis, synthetic methodologies are discussed, that were developed to gain control over the synthesis and the optoelectronic properties of colloidal Cu-chalcogenide nanomaterials, with special emphasis on alternative synthesis approaches. This thesis shows that by controlling the size, shape, composition and interactions of colloidal semiconductor nanocrystals, tailored materials can be prepared with high precision, which should possibly lead to unprecedented properties that will impact on a number of applications.