A novel donor–acceptor molecule containing a cyclic triphenylamine dimer: synthesis, characterization, and application in memory device

A novel highly soluble push–pull molecule containing electron-rich cyclic triphenylamine dimer (TPAD) and electron-poor N-phenyl-N′-octyl-naphthalene-1,4,5,8-tetracarboxylic acid bisimide [NI-(8,PBr)] was synthesized under Suzuki-coupling conditions. The resulting compound exhibited excellent thermal stability (Td=354.3 °C) and good solubility in common organic solvents. Cyclic voltammogram and optical absorption spectroscopy showed that both the electroactive units preserve their nature, respectively, in the ground state, whereas photophysical investigations showed a strong fluorescence quenching. Interestingly, excellent switching behavior with extremely high ON/OFF current ratio (1.6E8 at +1 V) was observed through memory devices based on thin films of this material.