Stable Solution-Processed High-Mobility Substituted Pentacene Semiconductors

The synthesis, photooxidative stability, and field-effect transistor properties of a series of 6,13-diethynyl-substituted pentacene derivatives are described. Substitution with appropriate solubilizing ethynyl functions at the C-6/C-13 positions of pentacene, which promote extended π-electron delocalization from the pentacene nucleus, leads to phenomenal enhancement in both solubility and photooxidative stability. This has enabled fabrication of a stable, solution-processed thin-film semiconductor under ambient conditions for high-mobility organic thin-film transistors. Specifically, a solution-processed 6,13-bis(4-pentylphenylethynyl)pentacene semiconductor has yielded mobility as high as 0.52 cm2 V-1 s-1 in OTFTs.