Solution processible naphthalene and perylene bisimides: Synthesis,electrochemical characterization and application to organic field effect transistors (OFETs) fabrication

A series of alkyl- or alkylphenyl-1,4,5,8-naphthalenetetracarboxylic-1,4:5,8-bisimides together with the comparative series of the corresponding 3,4,9,10-perylenetetracarboxylic-3,4:9,10-bisimides have been synthesized and characterized by cyclic voltammetry. The naphthalene bisimides family shows a clear dependence of its first reduction potential – corresponding to the LUMO level – on the nature of the N-substituent. Naphthalene bisimides containing alkylphenyl groups undergo the first 1e reduction at potentials of ca. 100 mV higher than those with alkyl groups (ca. −900 mV vs ca. −1000 mV with respect to Fc/Fc⁺ couple). No effect of the nature of the substituent is observed for the corresponding perylene bisimide series. Due to their improved solution processibility the synthesized organic semiconductors can be used for the fabrication of all organic, flexible n-channel field effect transistors (OFETs) through spin coating and printing techniques, without the necessity of the use of vacuum deposition techniques. The best of the fabricated transistors, operating in air show the charge carriers mobility of 4 × 10⁻² cm²/(V s) and the ON/OFF ratio equal to 4.5 × 10⁵.