Chiral self-assembly of p-quaterphenyl on semimetallic Bi(111) surface

• 1、School of Physical Science and Technology, Southwest University, Chongqing 400715

Abstract：The supramolecular chirality and self-assembly of p-quaterphneyl on the semimetallic Bi(111) surface have been investgated with a low temperature scanning tunneling microscopy (STM). It is found that there are flat-lying and edge-on molecules in the nanoclusters of p-quaterphneyl. In the submonolayer regime,p-quaterphneyl molecules form the self-assembled structure with multiple domains. The building bolcks of self-assemblies are molecular trimer with two flat-lying and one edge-on molecules. High-resolution STM images demonstrate that the flat-lying molecules have a planar achiral structure, while the edge-on molecules have a twisted chiral structure, which result in the supramolecular chirality of p-quaterphneyl strimers. Interestingly, theneighboring trimers inside the domains reveal opposite chirality, while the same chirality appears for the trimers at the domain boundaries, indicating the steric hindrance between the trimers with same handedness. When the voerage is increased to full monolayer, the domain boundaries disappear from the self-assembled structure, which have the long-range ordering with racemates. Moreover, due to the weak molecule-substrate interaction, both the flat-lying and the edge-on molecules can be moved or rotated under the electrical filed of STM tip. These results provide important information for the understadning of interaction between p-quaterphneyl and Bi(111) surface, the correlation between the supramolecular chirality and self-assembly, and realization of the organic-metal interface with long-range order.

Keywords： Supramolecular chirality p-quaterphenyl self-assembly STM domain boundary