Structure-Function Coupling in Pyridyl Triazole Copolymers for Neuromorphic Synaptic Transistors

Area of Science:

• Organic electronics
• Materials science
• Neuroscience

Background:

• Organic ferroelectric transistors are promising for low-cost synaptic devices.
• Donor-acceptor semiconducting polymers and poly-(vinylidene fluoride) (PVDF) copolymers are key for mimicking synaptic responses.

Purpose of the Study:

• Synthesize and evaluate novel pyridyl triazole (PyTr) based copolymers for synaptic transistor applications.
• Investigate the impact of linker units and semiconductor-dielectric interfaces on device performance and neuromorphic functionality.

Main Methods:

• Three PyTr copolymers with varied linkers (selenium-substituted thiophene, benzothiadiazole, fluorine-substituted thiophene) were synthesized.
• Transistor architectures using PVDF-HFP dielectric were fabricated to study p-type transport and carrier mobility.
• Synaptic plasticity was assessed via pulsed gate voltages, and neuromorphic functionality was tested in a multilayer perceptron for image recognition.

Main Results:

• Carrier mobilities ranged from 0.1 to 0.2 cm² V^-1 s^-1.
• The benzothiadiazole linker copolymer achieved ~80% image recognition accuracy.
• The fluorine-substituted thiophene linker copolymer exhibited no synaptic behavior, emphasizing interface importance.

Conclusions:

• The choice of linker unit significantly impacts synaptic transistor performance.
• The semiconductor-dielectric interface properties are critical for successful neuromorphic device operation.
• Further investigation into interface trap density and morphology is needed to optimize device design.