Delocalization and Mobility of Charge Carriers in Covalent Organic Frameworks

A new generally applicable method to calculate the relative energetic stability of localized and delocalized charges in a system of two molecules is presented. The relative stability of localized and delocalized charges was calculated for pi-stacked triphenylenes at varying twist angles and intermolecular distances. The reliability of the new method was validated by comparison with results from Hartree-Fock calculations on particular configurations. According to the calculations, charges are localized for larger twist angles that are typical for triphenylene derivatives in the liquid crystalline phase. In contrast, significant charge delocalization is expected for eclipsed stacking of triphenylene units in a covalent organic framework. This can give rise to band-like motion of delocalized charges with a mobility of the order of 10 cm(2) V(-1) s(-1) or more.