Tristable data storage device of soluble polyimides based on novel asymmetrical diamines containing carbazole

Abstract

Two new asymmetric diamines 9-(2′-bromobenzyl)-9H-carbazole-3,6-diamine (BBCDA) and 9-[2′-(3′′,4′′,5′′-trifluorophenyl)phenyl]-3,6-diaminocarbazole (TFDMC) were synthesised from carbazole. Tristable electrical conductivity switching and non-volatile memory effects are demonstrated in two novel soluble aromatic polyimides, which were prepared from BBCDA and TFDMC by polycondensation with pyromellitic dianhydride (PMDA) and 2,2′,3,3′-biphenyl tetracarboxylic dianhydride (BPDA) via a two-step procedure. All the three conductivity states are accessible, stable and non-erasable. It is noteworthy that the tristable phenomenon of the PI-based memory devices appeared in the process of “erasing”. The resulting polymers were fully characterized and they exhibited excellent organo-solubility and a high thermal stability with the temperature of 5% weight loss under a nitrogen atmosphere over 300 °C.