5,6,11,12-Tetrachlorotetracene, a tetracene derivative with π-stacking structure:: The synthesis, crystal structure and transistor properties

An important parameter for applications of organic semiconductor in devices is their charge-carrier mobility. It has been predicted theoretically that forming face-to-face pi-stacks at the molecular level may increase the charge-carrier mobility due to enhanced electronic couplings. To achieve different molecular arrangements, we recently synthesized and crystallized a tetracene derivative, 5,6,11,12-tetrachlorotetracene. The X-ray crystal structure shows that the molecules form slip pi-stacks in contrast to herringbone type tetracene. Comparison of electrostatic potential maps of tetrachlorotetracene and the parent tetracene molecule shows that the slip-stack packing structure is favored in terms of electrostatic forces due to the substituents in tetrachlorotetracene crystals. Single crystal field-effect transistors based on tetrachlorotetracene crystals show p-type behavior with a field-effect mobility of 1.7 cm(2)/V s, which is among the best values reported for organic field-effect transistors. These results, together with several recent findings, may serve as guidance in search of new organic semiconductors with high performance. (c) 2007 Elsevier B.V. All rights reserved.