Moradi, MinaOpara, Nadia L.Tulli, Ludovico G.Waeckerlin, ChristianDalgarno, Scott J.Teat, Simon J.Baljozovic, MilosPopova, Olhavan Genderen, EricKleibert, ArminStahlberg, HenningAbrahams, Jan PieterPadeste, CelestinoCorvini, Philippe F-XJung, Thomas A.Shahgaldian, Patrick2020-02-132020-02-132020-02-132019-02-0110.1126/sciadv.aav4489https://infoscience.epfl.ch/handle/20.500.14299/165328Stable, single-nanometer thin, and free-standing two-dimensional layers with controlled molecular architectures are desired for several applications ranging from (opto-)electronic devices to nanoparticle and single-biomolecule characterization. It is, however, challenging to construct these stable single molecular layers via self-assembly, as the cohesion of those systems is ensured only by in-plane bonds. We herein demonstrate that relatively weak noncovalent bonds of limited directionality such as dipole-dipole (-CN center dot center dot center dot NC-) interactions act in a synergistic fashion to stabilize crystalline monomolecular layers of tetrafunctional calixarenes. The monolayers produced, demonstrated to be freestanding, display a well-defined atomic structure on the single-nanometer scale and are robust under a wide range of conditions including photon and electron radiation. This work opens up new avenues for the fabrication of robust, single-component, and free-standing layers via bottom-up self-assembly.text::journal::journal article::research article