Soluble terthiophene-labeled cruciform molecule as a semiconductor for organic field-effect transistor

Cruciform conjugated molecule, 4(HP3T)-benzene bearing terthiophene moieties has been synthesized through Heck coupling reaction using 5-hexyl-5″-vinyl-[2,2′,5′,2″]terthiophene as dendrons and 1,2,4,5-tetrabromo-benzene as the core unit; this molecule has been fully characterized. This terthiophene-based molecule exhibits good solubility in common organic solvents and good self-film forming property. They are intrinsically crystalline as they exhibit well-defined X-ray diffraction patterns from uniform orientations of molecules. Thus, intermolecular interaction can be enhanced to affect the carrier transport phenomena after annealing at 160 °C. The semiconducting property of 4(HP3T)-benzene has been evaluated in organic field-effect transistors. 4(HP3T)-benzene exhibit carrier mobility as high as (3.7 ± 0.5) × 10−4 cm2 V−1 s−1 with an on/off ratio of about 1 × 103.