Colloidal quantum dot solids: Nanoscale control of the electronic properties

The interest in CQDs stems from the prospects of fully tunable electronic and optical properties and easy fabrication. Both of these features are advantageous for applications in solar cells and optoelectronic devices. However, for a very long time, the prospects remained unexploited in lack of deep knowledge on the chemistry and physics of the materials. Due to the large surface of the nanocrystals, different processes become dominant compared in comparison with bulk samples, and different characterization and treatment methods had to be developed to test and control the relevant properties. The knowledge in colloid chemistry had to be expanded making it suitable for the fabrication of highly pure, electronic-grade materials. This thesis demonstrates several ways of controlling the electronic properties of CQD arrays, the so-called CQD solids. These materials show much larger tunability of the electronic, electrical and optical properties than the bulk semiconductors, and show unique possibilities. Several questions and challenges are still open, but the results suggest that researchers will soon be in full control of the electronic properties of these materials, enabling commercial applications. The commercialization of CQDs solids in niche applications based on the tunable properties will certainly bring a new era in energy harvesting and (opto)electronics.