We report on the fabrication of a boron-based two-dimensional (2D) material via electron irradiation-induced cross-linking of carborane self-assembled monolayers (SAMs) on crystalline silver substrates. The SAMs of 1,2-dicarba-closo-dodecarborane-9,12-dithiol (O9,12) were prepared on flat crystalline silver substrates and irradiated with low-energy electrons, resulting in a 2D nanomembrane. The mechanical stability and compact character of the carborane nanomembrane were improved by using 12-(1',12'-dicarba-closo-dodecarboran-1'-yl)-1,12-dicarba-closo-dodecarborane-1-thiol (1-HS-bis-pCB), a longer, rod-like SAM precursor with two para-carborane units linked linearly together. The self-assembly, cross-linking process, and transfer of the resulting membranes onto holey substrates were characterized with different complementary surface-sensitive techniques including X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and low-energy electron diffraction (LEED) as well as scanning tunneling and electron microscopies (STM, SEM) to provide insight on the structural changes within the cross-linked SAMs. The presented methodology has potential for the development of boron-based 2D materials for applications in electronic and optical devices.

Center for Energy and Environmental Chemistry Jena Philosophenweg 7a 07743 Jena Germany

Central European Institute of Technology Purkyňova 123 612 00 Brno Královo Pole Czech Republic

Department of Chemistry Middle East Technical University Ankara 06800 Turkiye

Friedrich Schiller University Jena Institute of Physical Chemistry Lessingstraße 10 07743 Jena Germany

Jena Center for Soft Matter Philosophenweg 7 07743 Jena Germany

The Czech Academy of Sciences Institute of Inorganic Chemistry 250 68 Husinec Rez 1001 Czech Republic

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