Various Digital Memory Behaviors of Functional Aromatic Polyimides Based on Electron Donor and Acceptor Substituted Triphenylamines

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• 作者：Yong-Gi Ko ; Wonsang Kwon ; Hung-Ju Yen ; Cha-Wen Chang ; Dong Min Kim ; Kyungtae Kim ; Suk Gyu Hahm ; Taek Joon Lee ; Guey-Sheng Liou ; Moonhor Ree
• 刊名：Macromolecules
• 出版年：2012
• 出版时间：May 8, 2012
• 年：2012
• 卷：45
• 期：9
• 页码：3749-3758
• 全文大小：542K
• 年卷期：v.45,no.9(May 8, 2012)
• ISSN：1520-5835

文摘

A series of aromatic polyimides (PIs) were synthesized via the polymerization of 3,3鈥?4,4鈥?diphenylsulfonyltetracarboxylic dianhydride with 4,4鈥?diaminotriphenylamine derivatives containing hydrogen, cyano, methoxy, or dimethylamine substituents. These PIs were thermally and dimensionally stable and produced high-quality thin films when applied in a conventional spin-coating process. Their structure and properties were characterized. Nanoscale thin films of the PIs demonstrated excellent electrical memory performance, with high stabilities and ON/OFF current ratios. The memory characteristics were found to be tunable by varying the substituents; nonvolatile write-once鈥搑ead-many-times memory behavior, nonvolatile ON/OFF switching type memory behavior, and volatile dynamic random access memory behavior were observed. The memory characteristics were substantially influenced by the electron-accepting cyano- and electron-donating dimethylamine substituents but were apparently not affected by the electron-donating methoxy substituent. In addition, the film density was a significant factor influencing the observed memory behaviors, with larger film densities causing lower OFF-current levels. However, the critical switching-on voltage varied very little as the substituents were changed and was measured to be approximately 卤2 V. All of the memory behaviors were found to be governed by a mechanism involving trap-limited space-charge-limited conduction and local filament formation. Overall, all of the PIs assessed in the present work were found to be suitable active materials for the low-cost mass production of high-performance, programmable unipolar memory devices that can be operated with very low power consumption, high ON/OFF current ratios, and high thermal and dimensional stability.