Organic-Crystal Field-Effect Transistors Based on Terminal-Substituted Sexithiophenes

We have improved a vapor-phase crystal growth method. The method is characterized by a low-rate molecular gas flow under a quasi-equilibrium condition. The obtained crystals can be applicable to basic and applied research on organic devices. Using the present method, we grew crystals of terminal-substituted alpha-sexithiophene (6T) derivatives. These have phenyl substituent groups (P6T) or methyl substituent groups (M6T) at both molecular terminals. We made field-effect transistors using these crystals. Their maximum hole mobilities were more than 0.1 cm(2).V-1.s(-1). Of these devices, the P6T device showed light emissions under applied alternating-current gate voltages. The emissions became rapidly intense with increasing gate voltage amplitude. (C) 2013 The Japan Society of Applied Physics