Molecular Recognition and Band Alignment in 3D Covalent Organic Frameworks for Cocrystalline Organic Photovoltaics

Abstract

Covalent organic frameworks (COFs) have emerged as versatile, functional materials comprised of low-cost molecular building blocks. The permanent porosity, long-range order, and high surface area of 3D-COFs permit co-crystallization with other materials driven by supramolecular interactions. We designed a new subphthalocyanine-based 3-D covalent organic framework (NEUCOF1) capable of forming co-crystals with fullerene (C60) via periodic ball-and-socket binding motifs. The high co-crystalline surface area and long-range order of NEUCOF1 eliminates the typical surface area vs. structural order trade-off in organic photovoltaics (OPVs). We used plane-wave density functional theory (PBE) to minimize NEUCOF1 and NEUCOF1-C60 co-crystals and determine their electronic band structures. Molecular dynamics (MD) simulations showed that NEUCOF1-C60 is likely to be stable up to 350 K. The band structures at 0 and 350 K suggest that charge transfer to the C60 acceptors is favorable and that directional charge transport is possible for these co-crystalline OPVs.File list (1) download file view on ChemRxiv COF-JPC_C-resubmit1-final.docx (44.35 MiB)

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