W0215

Functionalized Acene Structures and Electronic Devices. Sean Parkin¹, David Eaton^1,2, Eric Bullock¹, Chad Landis¹, Susan Odom¹, James Brooks² and John Anthony¹, ¹Dept. of Chemistry, Univ. of Kentucky, Lexington, KY 40506. ²Dept. of Physics, Florida State Univ., Tallahassee, FL, 32310.

Crystal packing is the key property that governs the efficiency of organic electronic devices. Selective functionalization of acene molecules provides a degree of control over molecular orientation in both crystals and thin films. Starting with the most promising molecule for organic electronics, pentacene, we developed a scheme that leads to either slip–stacked, running–bond or columnar π–stacked motifs. These compounds, which differ only in the nature of alkyl substituents, have very different solid–state electronic properties. The running–bond derivatives have conductivities on the order of 10^-6 Scm^-1, slip–stacked derivatives around 10^-8 Scm^-1 and the columnar materials around 10^-9 Scm^-1. Other properties show equally dramatic dependence. Analysis of the crystal structures of these compounds has allowed us to increase the conductivity of pentacene by more than eight orders of magnitude.

Representative acene crystal structures of each type will be presented along with electronic devices made from them. These devices, which exploit the particular properties exhibited by the various packing motifs, include transistors and organic light–emitting diodes.