Controlled Migration of Lithium Cations by Diamine Bridges in Water-Processable Polymer-Based Solid-State Electrolyte...

Area of Science:

• Materials Science
• Neuroscience
• Electronics

Background:

• Biological synapses rely on signal retention for memory.
• Ion migration in solid-state electrolytes is key for high retention in synaptic transistors.
• Polymer-based electrolytes are underexplored for organic synaptic transistors (OSTRs).

Purpose of the Study:

• To develop water-processable polymer-based solid-state electrolytes (SSEs) for OSTRs.
• To investigate the effect of ion migration-controllable molecular bridges on OSTR performance.
• To demonstrate OSTRs capable of mimicking biological synaptic functions.

Main Methods:

• Fabrication of OSTRs using poly(4-styrenesulfonic acid) (PSSA), diethylenetriamine (DETA), and lithium hydroxide (LiOH) based SSEs.
• Tuning ion conductivity and device hysteresis by varying the DETA molar ratio (X) in PSSA:LiOH:DETA (PLiD) films.
• Evaluating synaptic plasticity through long-term potentiation and depression tests and artificial neural network simulations.

Main Results:

• Ion conductivity of PLiD films was significantly altered by DETA ratio, attributed to extended polymer chain distances.
• Optimal DETA ratio (X=0.2) resulted in significantly improved hysteresis and longest retention of current signals.
• Demonstrated gradual postsynaptic current buildup (potentiation) and adjustable depression via gate pulses.
• Achieved ≈96% accuracy in synaptic processes using artificial neural network simulations.

Conclusions:

• Water-processable polymer-based SSEs with ion migration-controlled bridges enable high-performance OSTRs.
• The developed OSTRs effectively mimic biological synaptic functions like potentiation and depression.
• These OSTRs show significant potential for applications in neuromorphic computing and artificial intelligence.