Monolayer and Bilayer Formation of Molecular 2D Networks Assembled at the Liquid/Solid Interfaces by Solution-Based Drop-Cast Method

Xingming Zeng; Yi Hu; Rongbin Xie; Sadaf Bashir Khan; Shern-Long Lee

doi:10.3390/molecules26247707

Monolayer and Bilayer Formation of Molecular 2D Networks Assembled at the Liquid/Solid Interfaces by Solution-Based Drop-Cast Method

Molecules. 2021 Dec 20;26(24):7707. doi: 10.3390/molecules26247707.

Authors

Xingming Zeng¹, Yi Hu¹, Rongbin Xie¹, Sadaf Bashir Khan^{1

2}, Shern-Long Lee¹

Affiliations

¹ Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China.
² Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.

Abstract

In recent years, extending self-assembled structures from two-dimensions (2D) to three-dimensions (3D) has been a paradigm in surface supramolecular chemistry and contemporary nanotechnology. Using organic molecules of p-terphenyl-3,5,3',5'-tetracarboxylic acid (TPTC), and scanning tunneling microscopy (STM), we present a simple route, that is the control of the solute solubility in a sample solution, to achieve the vertical growth of supramolecular self-assemblies, which would otherwise form monolayers at the organic solvent/graphite interface. Presumably, the bilayer formations were based on π-conjugated overlapped molecular dimers that worked as nuclei to induce the yielding of the second layer. We also tested other molecules, including trimesic acid (TMA) and 1,3,5-tris(4-carboxyphenyl)-benzene (BTB), as well as the further application of our methodology, demonstrating the facile preparation of layered assemblies.

Keywords: HOPG; STM; TPTC; bilayer; molecular self-assembly.