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

Abstract

A series of aromatic polyimides (PIs) were synthesized via the polymerization of 3,3′,4,4′-diphenylsulfonyltetracarboxylic dianhydride with 4,4′-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–read-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 ±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.

Structure and properties of new highly soluble aromatic poly(etherimide)s containing isopropylidene groups

“…[1][2][3] This unique combination of properties makes PIs ideal for a variety of applications, for example, in microelectronics, microelectromechanical systems, aerospace and photoelectronics or as gas separation membranes, materials for memory devices, alignment layers in liquid crystal displays, and redox-active, electrochromic polymers. [3][4][5][6] Although many excellent polyimides are known and commercially available, new polyimides are emerging as research continues on the chemical structure-property correlations and on the search for new compounds with unique combinations of properties for special applications. Recently, particular attention has been paid to new materials and technologies for gas separation applications because of environmental concerns and economic interests.…”

“…Xia et al 10 reported the gas permeability of a PEI that was synthesized from IPDA and diamino-diphenyl sulfone and compared it with those of polysulfone and Ultem. Lazareva et al 15 estimated the permeability and diffusion coefficients of H 2 , CO, CO 2 and CH 4 in two PEIs that were prepared from IPDA, 4,4 0 -(4,4 0 -isopropylidenediphenyl-1,1 0 -diyldioxy)dianiline, and 4,4 0 -(hexafluoroisopropylidene)bis(p-phenyleneoxy)diamine. Additionally, Ronova et al 16 described a correlation between the conformational rigidity of these PEIs and their gas permeabilities.…”

New photopatternable polyimide and programmable nonvolatile memory performances

“…[21][22][23][24][25] Although some of these materials have high dimensional and mechanical stability, their film forms are not sufficiently resilient to survive the device fabrication process. [31][32][33] Furthermore, they all lack patternability and thus can be patterned only with the aid of photoresist-based lithography techniques, significantly increasing the number of steps and the cost of device fabrication. Therefore, there is still an urgent need for low-cost printable, patternable, multi-stackable memory materials that are suitable for the fabrication of high-density memory devices and further integration with other electronic devices of various functionalities.…”

“…At the molecular design stage, a soluble, high-temperature polyimide (PI) was considered as the polymer backbone because it can provide solution processability, dimensional stability and thermal stability. 16,17,33,34 A photocrosslinkable functionality was also considered. Such a functionality can provide both large-area printability and photopatternability as a noncontact, negative-tone lithography tool.…”

Soluble N‐substituted poly(benzimidazole imide)s via C−N coupling reaction

“…In recent decades, heat‐resistant polymer materials have played an increasingly irreplaceable role in industries such as aerospace, machinery and electronics, and remarkable breakthroughs have been achieved in the development of heat‐resistant polymers . In particular, as one of the most promising classes of heat‐resistant engineering polymers, aromatic polyimides (PIs) have been widely used in the aerospace and microelectronics industry due to high thermal and dimensional stability, excellent mechanical properties, as well as good chemical and irradiation resistance . The unique chemical structure of PIs plays an irreplaceable role in their excellent properties .…”