Diacenopentalene dicarboximides as new n-type organic semiconductors for field-effect transistors

Abstract

N,N′-Dihexyl-dibenzopentalene dicarboximide (DBPDI) and N,N′-dioctyl-dinaphthopentalene dicarboximide (DNPDI) were successfully synthesized as new n-type semiconducting materials. They have good solubility in common organic solvents. DBPDI and DNPDI are thermally stable, with decomposition temperatures at 419 and 460 °C, respectively, based on thermogravimetric analysis, and melt at 354 and 387 °C as measured by differential scanning calorimetry. Their optical and electrochemical properties were studied by UV-vis absorption and cyclic voltammetry measurements. Time-dependent density functional theory calculations (TDDFT) were used to explain their unique electronic absorption spectra. DBPDI and DNPDI have relatively low-lying LUMO energy levels at -3.76 eV and -3.45 eV and HOMO energy levels at -5.84 eV and -5.72 eV, respectively. Their application in organic field-effect transistors (FETs) was investigated. Both DBPDI and DNPDI showed n-type field-effect transistor behavior. The DBPDI device obtained by solution-processing technique displayed an average electron mobility of up to 0.06 cm2 V-1 s-1 with an Ion/Ioff ratio of 2.9 × 106.