Naphthalenetetracarboxylic Diimide-Based N-Channel Transistor Semiconductors: Structural Variation and Thiol-Enhanced Gold Contacts

The synthesis and field-effect transistor (FET) electron mobility of ten N-substituted naphthalene 1,4,5,8-tetracarboxylic diimide (NTCDI) derivatives deposited at ambient and elevated temperatures are reported. Mobilities >0.01 cm sup 2/Vs were measured in air for three NTCDIs with partially fluroinated substituents, and >0.001 cm sup 2/Vs for a hydroxy- terminated compound. Mobilities 0.001-0.1 cm sup 2/Vs were also found for three n-alkyl NTCDIs, but only under vacuum. FET operation with gold bottom contacts was enabled by specific thiol coatings of the contacts. The highest mobility in air, >0.1 cm sup 2/Vs, was conferred by 4- trifluoromethylbenzyl substitution, while 1H, 1H-perfluorooctyl substitution resulted in an on/off ratio in air >10 sup 5. Solution electrochemistry and solid state x-ray and electron diffraction were employed to partially explain the results, and applications of the materials to complementary circuits are considered.