An Organic Flexible Artificial Bio-Synapses with Long-Term Plasticity for Neuromorphic Computing

Area of Science:

• Materials Science
• Neuroscience
• Computer Engineering

Background:

• Neuromorphic computing systems require artificial synapses with synaptic plasticity to mimic bio-synaptic functions.
• Traditional synaptic devices rely on silicon and inorganic materials, limiting flexibility.
• Organic electronics offer potential for developing flexible and adaptable synaptic devices.

Purpose of the Study:

• To propose and characterize a flexible artificial synaptic device utilizing an organic functional layer.
• To evaluate the device's performance in terms of switching behavior, synaptic plasticity emulation, and retention capabilities.
• To assess the device's potential for application in bio-inspired neuromorphic systems.

Main Methods:

• Fabrication of a flexible artificial synaptic device with an organic functional layer.
• Characterization of device switching behaviors, including ON/OFF ratio and operation voltages.
• Emulation of synaptic plasticity, including long-term plasticity, spike-timing-dependent plasticity (STDP), and forgetting functions.
• Measurement of retention times for excitatory and inhibitory post-synaptic currents.
• Assessment of device repeatability and stability over multiple voltage pulse cycles.

Main Results:

• The organic device exhibited excellent switching characteristics with an ON/OFF ratio exceeding 100 at low operating voltages (set voltage < 0.5 V, reset voltage < -0.25 V).
• The device successfully emulated key synaptic functions, including long-term plasticity, STDP learning rules, and forgetting.
• Excitatory and inhibitory post-synaptic currents demonstrated retention times longer than 60 seconds.
• The device showed repeatable long-term plasticity without significant degradation after five voltage pulse cycles.

Conclusions:

• The developed flexible organic artificial synapse demonstrates promising performance for neuromorphic computing.
• The device's ability to mimic synaptic plasticity and its flexibility make it suitable for bio-inspired computing applications.
• This research highlights the potential of organic electronics in advancing the field of neuromorphic engineering.