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Porous, stacked two-dimensional covalent organic frameworks (2D COFs) bearing semiconducting linkers can support directional charge transfer across adjacent layers of the COF. To better inform the current and possible future design rules for enhancing electron and hole transport in such materials, an understanding of how linker selection and functionalization affects interlayer electronic couplings is essential. We report electronic structure simulation and analysis of electronic couplings across adjacent linker units and to encapsulated species in functionalized electroactive 2D COFs. The detailed dependence of these electronic couplings on interlayer interactions is examined through scans along key interlayer degrees of freedom and through configurational sampling from equilibrium molecular dynamics on semiempirical potential energy surfaces. Beyond affirming the sensitivity of the electronic coupling to interlayer distance and orientation, these studies offer guidance toward linker functionalization strategies for enhancing charge carrier transport in electroactive 2D COFs. 

Abstract A three‐component synthesis methodology is described for the formation of covalent organic frameworks (COFs) containing extended aromatics. Notably, this approach enables synthesis of the building blocks and COF along parallel reaction landscapes, on a similar timeframe. The use of fragmental building block components, namely pyrene dione diboronic acid as aggregation‐inducing COF precursor and the diamineso‐phenylenediamine (Ph), 2,3‐diaminonaphthalene (Naph), or (1R,2R)‐(+)‐1,2‐diphenylethylenediamine (2Ph) as extending functionalization units in conjunction with 2,3,6,7,10,11‐hexahydroxytriphenylene, resulted in the formation of the corresponding pyrene‐fused azaacene, i.e., Aza‐COF series with full conversion of the dione moiety, long‐range order, and high surface area. In addition, the novel three‐component synthesis was successfully applied to produce highly crystalline, oriented thin films of the Aza‐COFs with nanostructured surfaces on various substrates. The Aza‐COFs exhibit light absorption maxima in the blue spectral region, and each Aza‐COF presents a distinct photoluminescence profile. Transient absorption measurements of Aza‐Ph‐ and Aza‐Naph‐COFs suggest ultrafast relaxation dynamics of excited‐states within these COFs.