<p>We have considered three two-dimensional (2D)
π-conjugated polymer networks (i.e., covalent organic frameworks, COFs)
materials based on pyrene, porphyrin, and zinc-porphyrin cores connected <i>via</i> 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<sup>2</sup>V<sup>-1</sup>s<sup>-1</sup>. 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 and surface area analysis, which
demonstrates the feasability of these electroactive networks.</p>
Two-dimensional hole gas in organic semiconductors
