Abstract
Objective of this study is the measurement and prediction of the effect of structural changes on the electronic properties of discotic liquid crystals (DLCs), an emerging class of organic semiconductors. Relative changes in frontier orbital energies of potentially discotic triphenylene (TP) and phthalocyanine (Pc) derivatives with different substitution patterns and substituents were predicted by gas phase molecular orbital calculations at a density functional theory (DFT) level. Calculations were performed with different basis sets and obtained frontier orbital energies are compared with experimental data of TP and Pc derivatives that have been studied by cyclic voltammetry (CV) and UV-Vis spectroscopy. Particular interest was given to a possible transition from p-type to n-type properties. A LUMO energy of 4.0 eV is used as reference point because this or lower LUMO energies have been proposed to provide potentially air stable n-type organic materials.