Effect of perfluorination on the charge-transport properties of organic semiconductors: density functional theory study of perfluorinated pentacene and sexithiophene

Density functional theory calculations were carried out to investigate the effect of perfluorination on the reorganization energy of charge-transport process. Fluorine substitution was found to increase the reorganization energy. disadvantageous for charge-transport. The enhancement of lambda is attributed to additional contributions from the stretching of C-F bonds. On the other hand. perfluorination tends to increase electron affinity and ionization potential of compounds, flavoring for electron- rather than hole-transport in viewpoints of thermodynamic stability and injection barrier charge. Based on these findings. valuable guidelines for the design of n-type materials with improved performance were proposed. (C) 2004 Elsevier B.V. All rights reserved.