Tristable Memory Devices Based on Soluble Polyimides Containing Pendant Carbazole and Phenyl Groups.

As an important component of highly functional macromolecule semiconductor, two kinds of new diamine monomers, bis(5‐amino‐6‐methoxy‐[1,1'‐biphenyl]‐3‐yl) methanone (BAMBPM) and bis(5‐amino‐4'‐(9H‐carbazol‐9‐yl)‐6‐methoxy‐[1,1'‐biphenyl]‐3‐yl) methanone (BACzMBPM) were used as raw materials. Two kinds of soluble aromatic polyimides were prepared from BAMBPM and BACzMBPM by polycondensation with 2,2',3,3'‐biphenyl tetracarboxylic dianhydride (BPDA) via a two‐step procedure. The obtained polyimides were sufficiently characterized, and showed superior organic solubility and excellent thermal stability, with a weight loss of 5 % weight loss above 300 °C. Memory devices with Al/polyimide/ITO structure were prepared by the traditional method of solution spin coating. Both devices show tristable characteristics, with high ON/OFF current ratios as high as 104 and long maintenance times of 104 seconds in the environmental atmosphere. [ABSTRACT FROM AUTHOR]