writer：Haiwei Tan, Huaxuan Yu, Ying Song, Shiyang Zhu, Bo Zhang, Hongyan Yao, Shaowei Guan
keywords：Hyperbranched polyimide, memory device
source：期刊
specific source：Journal of Polymer Science Part A: Polymer Chemistry, DOI:10.1002/pola.28920
Issue time：2017年

A series of ferrocene-terminated hyperbranched polyimides (HBPI-Fcs) were synthesized from a tetra-amine, bis (4-(3, 5-bis (4-amino-2-(trifluoromethyl) phenoxy) phenoxy) phenyl) methanon, and various dianhydrides, followed by termination with (4-amino) phenyl ferrocene. All the HBPI-Fcs possessed good organo-solubility and high thermal stability. The devices based on HBPI-Fcs exhibited bipolar and nonvolatile write-once-read-many times (WORM) memory performance with various threshold voltages and the same ON/OFF current ratio of 104. Moreover, the devices possessed excellent bistability under a constant bias of -1.00 V during a test period of 104 s. The different charge trapping ability of the electron-accepting moiety endowed the devices with different the threshold voltages. Mechanism analysis showed that the switching behavior was dominated by the charge trapping effect and the charge transfer was well fitted with the space-current-limited-current (SCLC) and ohmic model