Novel High-Performance Polymer Memory Devices Containing (OMe)2Tetraphenyl-p-phenylenediamine Moieties

The functional polyimide (OMe)(2)TPPA-6FPI (PI) and the polyamide (OMe)(2)TPPA-6FPA (PA) consisting of electron-donating NN-bis(4-aminophenyl)-N,N'-di(4-methoxylphenyl)1,4-phenylenediamine [(OMe)(2)TPPA-diamine] for memory application were prepared in this study. These polyimide and polyamide memory devices were fabricated with the sandwich configuration of indium tin oxide (ITO)/polymer/Al, and could be switched from the initial low-conductivity (OFF) state to the high-conductivity (ON) state with high ON/OFF current ratios of 10(7) and 10(9), respectively. PI exhibited dynamic random access memory (DRAM) performance, whereas PA showed static random access memory (SRAM) behavior. To get more insight into the memory behaviors of these two different types of polymer memory devices, molecular simulation on the basic unit was carried out. Furthermore, the differences of highest occupied molecular orbital (HOMO) energy level, lowest unoccupied molecular orbital (LUMO) charge density isosurfaces, dipole moment, and linkage conformation between PI and PA were found to affect the volatile memory behavior. Both polymer memory devices revealed excellent stability with long operation time of 10(4) s at continuous applied voltage of -2 V. The effect of polymer thickness on the volatile memory behavior of PA was also investigated in this study. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 3709-3718, 2011