Redox Switching Behavior in Resistive Memory Device Designed Using a Solution-Processable Phenalenyl-Based Co(II)...

Area of Science:

• Coordination Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Phenalenyl-derived ligands are electronically interesting and can form novel coordination complexes.
• Tetrathiafulvalene/tetracyanoquinodimethane charge transfer salts are known for their unique charge carrier interfaces due to π···π stacking.
• Resistive switching memory devices offer potential for advanced data storage applications.

Purpose of the Study:

• To synthesize and characterize a novel square-planar cobalt(II) complex using a phenalenyl-derived ligand.
• To investigate the supramolecular structure and π···π stacking interactions of the synthesized complex.
• To fabricate and evaluate a resistive switching memory device utilizing the synthesized complex as the active material.

Main Methods:

• Synthesis of a square-planar cobalt(II) complex [Co^IIL] with a phenalenyl-derived ligand (LH₂).
• Single-crystal X-ray diffraction for molecular structure determination.
• Supramolecular studies to analyze solid-state packing and π···π stacking.
• Fabrication and characterization of an indium tin oxide/Co^IIL/Al resistive switching memory device using write-read-erase-read cycles.
• Electrochemical characterization and density functional theory (DFT) studies.

Main Results:

• A novel mononuclear square-planar cobalt(II) complex, [Co^IIL], was successfully synthesized and structurally characterized.
• Supramolecular analysis revealed π···π stacking analogous to charge transfer salts, suggesting potential for charge carrier applications.
• The fabricated resistive switching memory device demonstrated stable and reproducible switching between two resistance states for over 2000 seconds.
• Electrochemical and DFT studies proposed a redox-resistive switching mechanism involving the cobalt(II) center and the phenalenyl backbone.

Conclusions:

• The synthesized [Co^IIL] complex possesses unique structural and electronic properties suitable for electronic device applications.
• The observed bistable resistive switching behavior highlights the potential of this complex in non-volatile memory technologies.
• The study provides insights into the structure-property relationships governing resistive switching in metal-organic complexes.