Accurate calculation of transport properties for organic molecular semiconductors with spin-component scaled MP2 and modern density functional theory methods

At ambient temperatures, intermolecular hopping of charge carriers dominates the field effect mobility and thus the performance of organic molecular semiconductors for organic-based electronic devices. We have used a wide variety of modern and accurate computational methods to calculate the main parameters associated with charge transport, taking oligoacenes, and its derivatives as the exemplary organic materials. We tackle the problem from a combined inter- and intramolecular approach, in which the parameters are calculated for an isolated single molecule concomitantly with the stability of the dimers found in experimentally determined crystalline structures. Considering that most of the future applications within the field would need a full understanding of the transport mechanism, we assess the reliability of the methods to be employed according to the nature of the problem. Finally, we perform a computationally guided molecular engineering of a new set of materials derived from tetracene (rubrene and highly twisted oligoacenes) which allows to robustly anticipate the reasons for their expected performance in organic-based electronic devices. (c) 2008 American Institute of Physics.