In-situ Study of Quantum Dots Self-assembly into 3D superlattices at the air/liquid interface

In this proposal we aim to understand the formation mechanism of 3D superlattices (3D-SLs) (up to 100 nm thick, i.e. 12 layers) of PbSe colloidal quantum dots (QDs) in the presence and during removal of the native oleic acid ligands. We plan to achieve this by using the combination of in-situ simultaneous GISAXS and GIWAXS at the liquid interface under controlled solvent evaporation conditions. Controlling the removal of insulation long alkyl chain ligands is key to tune the QD array’s stoichiometry and structure in the range necessary to manipulate the density of states and charge transport, allowing to fabricate materials with high optoelectronic performances. By performing this in-situ experiment, we will determine the optimum conditions to achieve maximum order in the ligand-capped QD SLs and understand how to minimize the loss of structural order during ligand removal.