Molecular Ligands Control Superlattice Structure and Crystallite Orientation in Colloidal Quantum Dot Solids

Abstract

Colloidal quantum dot solids represent a new materials platform that has garnered interest for a variety of electronic, optoelectronic, and photovoltaic applications. In such solids, individual quantum dots must be coupled with each other to facilitate charge transport through the solid. Past improvements on charge transport of colloidal quantum dot solids have been achieved primarily through the control of the interparticle spacing. However, the role of morphological ordering of the crystalline facets of individual quantum dots on the charge transport of the quantum dot solid is unknown. Here, we show for the first time that small passivating ligand molecules around the quantum dots can control the arrangement of different facets of quantum dots within the quantum dot solid. The insights from this study provide important directions for future enhancement in orientation of quantum dots in colloidal quantum dot solids.