Abstract
We have considered three two-dimensional (2D) π-conjugated polymer network (
i.e.
, covalent organic frameworks, COFs) materials based on pyrene, porphyrin, and zinc-porphyrin cores connected
via
diacetylenic linkers. Their electronic structures, investigated at the density functional theory global-hybrid level, are indicative of valence and conduction bands that have large widths, ranging between 1 and 2 eV. Using a molecular approach to derive the electronic couplings between adjacent core units and the electron-vibration couplings, the three π-conjugated 2D COFs are predicted to have ambipolar charge-transport characteristics with electron and hole mobilities in the range of 65–95 cm
2
V
−1
s
−1
. Such predicted values rank these 2D COFs among the highest-mobility organic semiconductors. In addition, we have synthesized the zinc-porphyrin based 2D COF and carried out structural characterization
via
powder X-ray diffraction, high-resolution transmission electron microscopy, and surface area analysis, which demonstrates the feasibility of these electroactive networks. Steady-state and flash-photolysis time-resolved microwave conductivity measurements on the zinc-porphyrin COF point to appreciable, broadband photoconductivity while transmission spectral measurements are indicative of extended π-conjugation.