High Performance Volatile Polymeric Memory Devices Based on Novel Triphenylamine-based Polyimides Containing Mono- or Dual-Mediated Phenoxy Linkages

Two novel functional polyimides (PIs), PI(AAPT-TPA) and PI(APT-TPA), consisting of electron-donating 4-amino-4′-(p-aminophenoxy)-triphenylamine (AAPT) or 4,4′-bis(p-aminophenoxy)-triphenylamine (APT) and electron-accepting phthalimide moieties, were prepared for the memory device applications. The TPA moieties as electron donor are expected to enhance the electron donating and charge transport ability with phthalimide moieties (electron acceptor). The monophenoxy linkage PI(AAPT-TPA) had a higher Tg and a lower band gap than the dual-phenoxy linkage PI(APT-TPA). It suggested the more rigid backbone of the former and led to different memory characteristics. The memory devices with the configuration of ITO/PI/Al exhibited two conductivity states and could be swept positively or negatively with a high ON/OFF current ratio of 108−109. The PI(AAPT-6FDA) device relaxed from the ON state to the OFF state quickly after the applied voltages was removed, whereas the ON state of the PI(APT-6FDA) device could remain ...