Bistable memory devices with lower threshold voltage by extending the molecular alkyl-chain length

Area of Science:

• Materials Science
• Organic Electronics
• Nanotechnology

Background:

• Organic small molecules offer tunable electronic properties for advanced memory devices.
• Azobenzene derivatives are promising candidates for molecular electronics due to their photoresponsive and structural characteristics.
• Controlling thin-film morphology is crucial for optimizing the performance of organic electronic devices.

Purpose of the Study:

• To design and synthesize novel azobenzene-based organic small molecules with varying alkyl chain lengths.
• To investigate the effect of alkyl chain length on the performance of indium-tin oxide (ITO)-Azo-Al sandwich memory devices.
• To correlate molecular structure and thin-film properties with device characteristics.

Main Methods:

• Synthesis of three organic small molecules based on an azobenzene scaffold with different alkyl chain lengths.
• Fabrication of indium-tin oxide (ITO)-Azo-Al sandwich memory devices.
• Electrical characterization of device performance, including switch threshold voltage.
• Atomic Force Microscopy (AFM) and X-ray diffraction (XRD) analysis of thin-film morphology and molecular packing.

Main Results:

• The fabricated memory devices exhibited write-once-read-many-times (WORM) characteristics.
• A significant decrease in switch threshold voltage was observed with increasing end-capping alkyl chain length.
• AFM and XRD results indicated smoother thin-film morphologies and closer intermolecular packing as alkyl chain length increased.
• Alkyl chain length directly influences thin-film microstructure and intermolecular arrangement.

Conclusions:

• Variation in alkyl chain length is an effective strategy for tuning the microstructure and intermolecular packing of azobenzene-based organic materials.
• Optimizing molecular design, specifically alkyl chain length, enables enhanced performance in fabricated sandwiched memory devices.
• This study provides insights into structure-property relationships for developing high-performance organic electronic memory.