Integrating bi-radical units (a) into 2D-CORFs (b) allows for reversible switching between the two configurations via applied uniaxial strain.
A collaborative theoretical study involving three groups from the Institute of Theoretical and Computational Chemistry of the University dofe Barcelona (IQTCUB), published in Nature Communications, shows how to reversibly switch between electronic states in organic materials.
The paper was also featured as an Editor's Highlight and as a Behind the paper article signed by Stefan Bromley, ICREA Research Professor at IQTCUB and principal researcher in this study.
Since the discovery of graphene, an increasing number of inorganic 2D materials with a range of physical and chemical properties have been synthesized by top-down approaches. However, in practice, these 2D inorganic materials possess very high in-plane tensile strengths, which only allow for moderate strains generating modest electronic changes. At the same time, chemists have developed alternative bottom-up synthesis approaches based on linking arrays of molecular building blocks, to produce 2D covalent organic frameworks (called 2D-COFs).
The IQTCUB authors in this study show, in a theoretical way, that a certain family of 2D-COF can provide an ideal base to control electronic properties through the strain-control. The use of 2D-CORFs blocks can provide a platform for new flexible materials in which optical, magnetic and electrical properties can be reversibly controlled by modest structural strain. "This is a fundamental challenge for future sub-nanoscale device technologies, but the external dynamical control of these states still awaits experimental realization" says Stefan Bromley.
Article reference
Isaac Alcón, Raúl Santiago, Jordi Ribas-Arino, Mercè Deumal, Ibério de P. R. Moreira & Stefan T. Bromley. "Controlling the pairing of π-conjugated electrons in 2D covalent organic radical frameworks", Nature Communications, 12, 1705 (2021). Doi: 10.1038/s41467-021-21885-y
