Patterned growth of large oriented organic semiconductor single crystals on self-assembled monolayer templates.

This work demonstrates a method for inducing site-specific nucleation and subsequent growth of large oriented organic semiconductor single crystals using micropatterned self-assembled monolayers (SAMs). We demonstrate growth of oriented, patterned, and large organic semiconductor single crystals for potential use in organic electronic devices. The control over multiple parameters in a single system has not yet been reported. The ability to control various aspects of crystal growth in one system provides a powerful technique for the bottom-up fabrication of organic single-crystal semiconductor devices.

Synthesis, crystal structure, and transistor performance of tetracene derivatives.

The substitution of chloro or bromo groups in tetracene gives rise to the change of crystal structure, having a substantial effect on carrier transport. Halogenated tetracene derivatives were synthesized and grown into single crystals. Monosubstituted 5-bromo- and 5-chlorotetracenes have the herringbone-type structure, while 5,11-dichlorotetracene has the slipped pi stacking structure. Mobility of 5,11-dichlorotetracene was measured to be as high as 1.6 cm2/V.s in single-crystal transistors. The pi stacking structure, which enhances pi orbital overlap and facilitates carrier transport, may thus be responsible for this high mobility.