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Non-volatile memory devices based on polystyrene derivatives with electron-donating oligofluorene pendent moieties
Cheng-Liang Liu1, Jung-Ching Hsu, Wen-Chang Chen
1Department of Chemical Engineering and Institute of Polymer Science and Engineering, National Taiwan University, Taipei, Taiwan 10617.
ACS Applied Materials & Interfaces
|April 2, 2010
Summary
We developed novel non-volatile memory devices using polystyrene derivatives with varying fluorene chain lengths. Device performance, including lower threshold voltages, was tuned by adjusting polymer structure and processing for enhanced flash memory applications.
Area of Science:
- Materials Science
- Organic Electronics
- Polymer Chemistry
Background:
- Non-volatile memory devices are crucial for modern electronics.
- Tuning polymer properties is key to improving memory device performance.
- Fluorene-based polymers offer promising characteristics for electronic applications.
Purpose of the Study:
- To investigate bistable non-volatile memory devices based on polystyrene derivatives with pendent fluorene units.
- To explore the impact of oligofluorene chain length and polymer surface structure on memory characteristics.
- To elucidate the mechanism behind the switching behavior in these polymer memory devices.
Main Methods:
- Synthesis of polystyrene derivatives with mono-, di-, and tri(9,9-dihexylfluorene) units (poly(St-Fl), poly(St-Fl(2)), poly(St-Fl(3))).
- Fabrication and characterization of memory devices using these polymers.
- Analysis of electrical properties including turn-on threshold voltage, ON/OFF current ratio, and retention time.
- Investigation of polymer thin film morphology and its correlation with device performance.
Main Results:
- Devices exhibited flash memory characteristics with decreasing turn-on threshold voltages (2.8 V, 2.0 V, 1.8 V) corresponding to increasing oligofluorene chain lengths.
- A high ON/OFF current ratio (2.5 x 10^4) and long retention time (10^4 s) were achieved.
- Space-charge-limited current and filamentary conduction mechanisms were proposed for the switching behavior.
- Larger aggregation domain size in polymer films processed from mixed solvents reduced the turn-on threshold voltage.
Conclusions:
- Polymer memory characteristics can be effectively tuned by controlling pendent conjugated chain length and surface structures.
- The study demonstrates a viable route for developing high-performance organic memory devices.
- Optimized polymer processing and molecular design are critical for reducing operating voltages and enhancing memory device functionality.
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