Two-Dimensional Crystallization of Rylene Diimide Based n-Type Semiconductors Tuned by the Dimensions of the Aromatic Core at the Liquid-Solid Interface

The investigation of semiconductors at the surface provides opportunities to observe and understand the mechanism of molecular interaction for the design of semiconductors so that organic electronics with good performance can be built. Herein, the 2D crystallization of rylene diimide based n-type semiconductors (i.e., 1-4) was explored at the liquid-highly oriented pyrolytic graphite interface by means of scanning tunneling microscopy. Rylene diimides 1-3 with increased aromatic dimensions show different surface crystallization behaviors and distinguished 2D patterns. The surface chirality was also found to be directly affected by the aromatic dimensions. The 2D patterns and the surface chirality could also be tuned by the nature of the solvent. In addition, molecular symmetry was found to be of great important for the formation of long-range ordered 2D monolayers. This investigation highlights the importance of the rational design of molecular dimensions and geometrical symmetry in achieving determined 2D nanopatterns on surfaces, especially for the rylene diimide based n-type semiconductors.