Engineering flat and dispersive bands in 2D layered COFs via interlayer stacking and donor-acceptor strategy

07 March 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Covalent organic frameworks (COFs) are an emergent class of two-dimensional (2D) crystalline organic materials that exhibit unique electronic, optical, and transport properties. In this study, we employ density functional theory (DFT) and the multiparticle Holstein formalism (MHF) to investigate the electronic structure and two-dimensional coherence of polarons in donor-acceptor COFs as a function of interlayer stacking arrangement. We show that simple modifications in the interlayer stacking arrangement have a profound impact on the transport properties, which can range from metallic behavior with vanishing band gap to highly localized states having completely flat bands. The extent of charge delocalization is found to be sensitive to the type of stacking arrangement and the precise arrangement of the donor and acceptor fragments within the COF structure. The results from the DFT calculations are consistent with MHF-based simulations, demonstrating that stacking-induced interlayer interac- tions facilitate better in-plane charge delocalization. As a consequence, we find that interlayer interactions help circumvent defect-induced trap states to enhance overall charge delocalization. Based on these analyses, we conclude that interlayer stacking can be exploited to guide the design of new 2D layered COF structures with potential applications in organic electronics.


covalent organic frameworks
electronic structure
band gap
density functional theory
charge transport
Holstein Hamiltonian
electronic band structure

Supplementary materials

Supporting Information
Detailed discussions of effective mass, electronic band structures, and partial charge densities.


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