High-performance organic semiconductors: asymmetric linear acenes containing sulphur

Two new linear acenes with fused thiophene units have been synthesized. These acenes have conjugation lengths between anthracene and pentacene. Thin films of these linear molecules were characterized by ultraviolet spectroscopy, X-ray diffraction, atomic force microscopy (AFM), and field-effect transistor measurements. Submonolayer AFM studies show growth that greatly resembles pentacene, while thin-film growth is dendritic. Mobilites as high as 0.47 cm2 V-1 s-1 have been found for the tetraceno2,3-b]thiophene and are as high as 0.15 cm2 V-1 s-1 for anthra2,3-b]thiophene.