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Organo‐Solubility Carbazole‐Containing Polyimides with Tunable Memory Characteristics Based on Different Dianhydride Moieties
Author(s) -
Yang Yanhua,
Jin Pan,
Ding Shijin,
Chu Yueying,
Shen Yingzhong
Publication year - 2018
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.201800195
Subject(s) - bpda , biphenyl , carbazole , solubility , diamine , polymer chemistry , materials science , polymer , chemistry , polyimide , photochemistry , organic chemistry , nanotechnology , layer (electronics) , composite material
A novel asymmetric carbazole‐based diamine (9‐((4′‐(9 H ‐carbazolyl)‐[1,1′‐biphenyl])methyl)‐3,6‐diaminocarbazole (BCDA‐CBZ)) is synthesized and characterized. Two aromatic conjugated polyimides (PI‐a and PI‐b) are prepared via a two‐step procedure using BCDA‐CBZ reacting with 2,2′,3,3′‐biphenyl‐tetracarboxylic dianhydride ( i ‐BPDA) and 2,2′‐bis(4′‐phenyl)‐4,4′,5,5′‐biphenyltetracarboxylic dianhydride (DPBPDA), respectively. The resulting PIs possess excellent organo‐solubility, are thermally stable, and have film‐formation ability. The Al/PI‐a/ITO exhibits a dynamic random access memory behavior, whereas the Al/PI‐b/ITO presents a rewritable type memory capability. The fabricated PI‐a device shows low turn‐on threshold voltages at −1.47 and +2.85 V, and the switching voltages of PI‐b device are −2.07 (turn‐on) and +2.85 V (turn‐off). The electrical conduction behaviors are analyzed using theoretical models based on the experimental data. The molecular simulation by density functional theory calculations suggests that field‐induced charge‐transfer and the conformation change mechanism could be used to explain the memory characteristics.