Memristive Switching Characteristics in Biomaterial Chitosan-Based Solid Polymer Electrolyte for Artificial Synapse.

Area of Science:

• Materials Science
• Neuroscience
• Electronics

Background:

• Organic memristors offer potential for advanced electronics but suffer from unstable multilevel states and poor reliability.
• Biomaterial solid polymer electrolytes (SPE) present an alternative for developing more robust memristive devices.

Purpose of the Study:

• To evaluate the memristive switching characteristics of a chitosan-based SPE memristor.
• To confirm its artificial synaptic behavior with analog switching capabilities.
• To address the limitations of unstable multilevel states and poor reliability in organic memristors.

Main Methods:

• Fabrication of a Ti/SPE-chitosan/Pt memristor device.
• Evaluation of bipolar resistive switching (BRS) behavior and endurance.
• Achieving multilevel per cell (MLC) BRS characteristics via analog switching by adjusting set compliance current (Icc).
• Analysis of conductive filament formation and its relationship with operating parameters.

Main Results:

• The Ti/SPE-chitosan/Pt memristor exhibited stable BRS behavior attributed to cation-based electrochemical reactions.
• The device demonstrated excellent endurance over 5 × 10^2 DC cycles.
• Stable MLC BRS I-V characteristics were achieved with uniform resistance distributions and nonvolatile retention (>10^4 s).
• Continuous analog resistance switching was indicated by the multilevel resistance dependence on Icc.
• Chitosan-based SPE artificial synapses successfully emulated biological synaptic plasticity (short- and long-term).

Conclusions:

• Chitosan-based SPE memristors offer stable bipolar resistive switching and reliable analog multilevel states.
• These devices demonstrate significant potential for emulating biological synapses, paving the way for neuromorphic computing.
• The study overcomes key reliability and stability challenges in organic memristive devices.