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O: Fachverband Oberflächenphysik
O 39: Poster Session III: Poster to Mini-Symposium: Free-standing functional molecular 2D materials I
O 39.1: Poster
Tuesday, March 2, 2021, 10:30–12:30, P
Electronic and Optical Properties of Protonated Triazine Derivatives — •Michele Guerrini1,2, Enrique Delgado Aznar2, and Caterina Cocchi1,2 — 1Carl von Ossietzky Universität Oldenburg, Institute of Physics, 26129 Oldenburg, Germany — 2Humboldt-Universität zu Berlin, Physics Department and IRIS Adlershof, 12489 Berlin, Germany
The peculiar electronic and optical properties of covalent organic frameworks (COFs) are largely determined by protonation, a ubiquitous phenomenon in solution environments. Resulting effects are non-trivial and yet crucial for the intriguing functionalities of these materials. We investigate from first principles the impact of protonation of triazine and amino groups in molecular building blocks of COFs in water solution. We find that proton uptake leads to bandgap reduction and to a reorganization of the electronic structure. The interplay between bandgap renormalization and exciton binding strength determines whether the absorption onsets is red or blue shifted with respect to the pristine species. Structural distortions induced by protonation are found to play only a minor role.Our results [1] offer a quantitative and microscopic insight into the role of protonation in the electronic and optical response of triazine derivatives as building blocks of COFs and to the rationalization of the relationship between structure, property, and functionality in these materials.
[1] M. Guerrini, E. D. Aznar, C. Cocchi J. Phys. Chem. C 2020 DOI: 10.1021/acs.jpcc.0c08812