Rewritable and Non-Volatile Memory Effects Based on Polyimides Containing Pendant Carbazole and Triphenylamine Groups

As part of a strategy to explore highly functionalized macromolecular semiconductors, two novel polyimides consisting of electron-donating carbazole and triphenylamine side groups are synthesized and characterized. Polyimide films sandwiched between an indium-tin oxide (ITO) bottom electrode and Al top electrode exhibit two accessible conductivity states and can be switched from the low-conductivity state to the high-conductivity state. Memory devices with the configuration of Al/PI(CzBD-DPBPDA)/ITO exhibit bipolar flash-type memory characteristics while that of Al/PI(TPABD-DPBPDA)/ITO demonstrate excellent unipolar ON and OFF switching behavior. Both devices show high ON/OFF current ratios up to 10(4) and long retention times of 10(4) s in ambient atmosphere.