n- and p-Channel field-effect transistors based on diquinoxalinoTTF derivatives

Three new quinoxalinoTTF derivatives with methyl, trifluoromethyl and fluoro groups were synthesized and characterized by UV–vis absorption spectroscopy, differential scanning calorimetry, X-ray single crystal analysis, X-ray diffraction, and field-effect transistor (FET) characteristics. All of them have π-stacking structures in the single crystals. The quinoxalinoTTF derivative with trifluoromethyl groups exhibited an n-type FET, which is a rare example of n-channel FETs based on TTF derivatives. The highest electron mobility is 0.01 cm2 V−1 s. The FET polarity was converted to p-channel from n-channel by replacing the trifluoromethyl groups with methyl groups. The hole mobility is as high as 0.2 cm2 V−1 s. In contrast, the fluoro substituted derivative did not show FET properties due to the poorly ordered molecular arrangement.