Discotic Liquid Crystal-Functionalized Gold Nanorods: 2-and 3D Self-Assembly and Macroscopic Alignment as well as Increased Charge Carrier Mobility in Hexagonal Columnar Liquid Crystal Hosts Affected by Molecular Packing and π-π Interactions

Gold nanorods functionalized with triphenylene-based discotic liquid crystal (LC) motifs show striking self-assembly behavior both on transmission electron microscopy (TEM) grids as well as in the bulk enforced by the pi-pi-stacking of triphenylene groups of adjacent nanorods. TEM images confirm that these discotic LC nanorods form ribbons of parallel-stacked nanorods several hundred nanometer long. The pursued silane conjugation approach to decorate the nanorods allows for the preparation of dispersions of the nanorods in the hexagonal columnar phases of parent discotic LCs, where the nanorods can be macroscopically aligned with almost 80% efficiency by a simple shearing protocol. Doping the parent host materials with about 1% by weight of the discotic LC-capped nanorods also reduces the lattice parameter and the intracolumnar packing, which gives rise to enhanced charge carrier mobility in these hosts as determined by time-of-flight measurements.