Kinetic control of self-assembly using a low-energy electron beam

• Published in: Applied surface science 2022-10, Vol.600, p.154106, Article 154106
• Main Authors: Makoveev, Anton, Procházka, Pavel, Shahsavar, Azin, Kormoš, Lukáš, Krajňák, Tomáš, Stará, Veronika, Čechal, Jan
• Format: Article
• Language: English
• Subjects: Kinetics; Low-Energy Electron Microscopy; On-Surface Reactions; Self-Assembly; Surfaces
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2022.154106

[Display omitted] •Selective enhancement of a reaction step by low-energy electrons.•Distinct self-assembled phases depending on electron energy.•A unique non-thermal self-assembled phase.•A stable intermediate state for on-surface deprotonation. Self-assembly and on-surface synthesis are vital strategies used for fabricating surface-confined 1D or 2D supramolecular nanoarchitectures with atomic precision. In many systems, the resulting structure is determined by the kinetics of the processes involved, i.e., reaction rate, on-surface diffusion, nucleation, and growth, all of which are typically governed by temperature. However, other external factors have been only scarcely harnessed to control the on-surface chemical reaction kinetics and self-assembly. Here, we show that a low-energy electron beam can be used to steer chemical reaction kinetics and induce the growth of molecular phases unattainable by thermal annealing. The electron beam provides a well-controlled means of promoting the elementary reaction step, i.e., deprotonation of carboxyl groups. The reaction rate increases with the increasing electron beam energy beyond the threshold energy of 6 eV. Our results offer the novel prospect of controlling self-assembly, enhancing the rate of reaction steps selectively, and thus altering the kinetic rate hierarchy.