Wafer-Scale Unidirectional Alignment of Supramolecular Columns on Faceted Surfaces

Abstract

The long-range alignment of supramolecular structures must be engineered as a first step toward advanced nanopatterning processes aimed at miniaturizing features to dimensions below 5 nm. This study introduces a facile method of directing the orientation of supramolecular columns over wafer-scale areas using faceted surfaces. Supramolecular columns with features on the sub-5 nm scale were highly aligned in a direction orthogonal to that of the facet patterning on unidirectional and nanoscopic faceted surface patterns. This unidirectional alignment of supramolecular columns is also observed by varying the thickness of the supramolecular film or by altering the dimensions of the facet pattern. The ordering behavior of the supramolecular columns can be attributed to the triangular depth profile of the bottom facet pattern. Furthermore, this directed self-assembly principle allows for the continuous alignment of supramolecular structures across ultralarge distances on flexible patterned substrates.

Columnar Mesomorphism in a Methylthio-Decorated Triindole for Enhanced Charge Transport

“…The reason lies in their characteristic structure, which is built from molecules surrounded by long flexible alkyl chains. , This structure induces phase segregation, promoting the arrangement of aromatic cores in columns favorable for efficient intracolumnar transport, but also results in melted alkyl chains forming an isolating cover, preventing intercolumnar charge transport. Consequently, the charge transport is highly uniaxial, making it highly dependent on the alignment of the columns on the substrates. − While obtaining the necessary macroscopic orientation of columns on different substrates has been successfully achieved through diverse strategies, including the application of electric fields, shearing, surface treatments, or confinement effects, solutions to date vary across different materials and it still poses a notable challenge for the fabrication of easily processed devices. To reduce the alignment dependence, discotic molecules with less alkyl chains are preferred, , thereby leading to discotic mesophases with a high conductor-to-insulator ratio.…”

“…Consequently, the charge transport is highly uniaxial, making it highly dependent on the alignment of the columns on the substrates. 28 − 30 While obtaining the necessary macroscopic orientation of columns on different substrates has been successfully achieved through diverse strategies, including the application of electric fields, 31 shearing, 32 surface treatments, 33 or confinement effects, 34 solutions to date vary across different materials and it still poses a notable challenge for the fabrication of easily processed devices. To reduce the alignment dependence, discotic molecules with less alkyl chains are preferred, 30 , 35 thereby leading to discotic mesophases with a high conductor-to-insulator ratio.…”