Synthesis and memory characteristics of novel soluble polyimides based on asymmetrical diamines containing carbazole

•Two diamines (BNBCD, CBMCD) and four novel soluble polyimides have been prepared.•The resulting polymers were fully characterized by UV-vis, PL, TGA, CV, XRD, etc.•PI-a, PI-b and PI-c showed flash type memory traits, PI-d showed a WORM type.

Two novel asymmetrical carbazole-based diamines 9-(2-(1,1′-binaphthyl-4-yl)benzyl)-9H-carbazole-3,6-diamine (BNBCD) and 9-((4′-(9H-carbazol-9-yl)biphenyl-2-yl)methyl-9H-carbazole-3,6-diamine (CBMCD) were synthesized. A series of novel soluble aromatic polyimides were prepared from these diamines by poly-condensation with Pyromelitic dianhydride (PMDA) and 2,2′,3,3′-biphenyl tetracarboxylic dianhydride (BPDA) via a two-step procedure. The resulting polymers were fully characterized, they exhibited excellent organosolubility and high thermal stability with the temperature of 5% weight loss under nitrogen atmosphere over 400 °C. Resistive switching devices with the configuration of Al/polymer/ITO were constructed from these polyimides by using conventional solution coating process. The memory devices based on PI-a, PI-b and PI-c exhibited a flash type memory capability, whereas the PI-d presented a write once read many times (WORM) memory capability.

Graphical abstractFour novel soluble carbazole-containing polyimides were prepared from BNBCD and CBMCD by poly-condensation with Pyromelitic dianhydride (PMDA) and 2,2′,3,3′-biphenyl tetracarboxylic dianhydride (BPDA) via a two-step procedure. The PI-based devices exhibited flash type memory behaviors and WORM memory character.Download full-size image