Stabilization of Pristine Low Resistive State in a Ruthenium(II)‐Polymer of a Hexadentate Schiff Base Ligand: Synthesis, Characterization, and Application as Non‐Volatile Memory Device

Abstract

Metallo‐supramolecular polymers offer ample opportunity to develop new emergent materials with the potential for applications as future memories. In this context, we have synthesized a novel hybrid polymer of our developed Schiff base ligand with Ru(II)‐metal ion. The main objective of this study is to understand the effect of changing central metal ion on the ligand field stabilization energy, and the band gap of material as the biting angle of organic moiety changes accordingly with a change in cationic radius of the central metal ion. Furthermore, we have also investigated the application in non‐volatile memory devices. Complete characterization of the newly synthesized hybrid polymer has been performed to establish its structure as well as oxidation state of the central metal ion. A comparative study of the present case and the previously reported Fe(II)‐polymer provides a clear insight into the effect of incorporating a bigger size metal ion in the polymer chain. Non‐volatile memory properties of the polymer have shown a rare behaviour of Negative Differential Resistance (NDR) along with the Low Resistive State (LRS) as its pristine state. Remarkable charge retention and endurance test have also been demonstrated.

Metal-containing organic compounds for memory and data storage applications

“…In 2020, to discover the effects of metal center on ligand field stabilization energy, bandgap, and configuration of molecules, Bandyopadhyay et al designed and synthesized a new Ru(II)hybrid polymer with hexadentate Schiff base ligand (P37). 157 The P37-based device (ITO/P37/Al) showed a bipolar non-volatile resistive-switching behavior, resulting from the redox reaction between CT complexes of Ru ion and ligand. Moreover, the bandgap of P37 was also decreased because the bigger size of central metal ion Ru(II) enabled a better overlap of molecular orbitals of central metal ion and ligand, allowing the LRS as a pristine state of the device.…”