Visible-Light-Responsive Organic Synaptic Devices Based on Rhodamine B-Doped Source-Gated Transistors

Area of Science:

• Materials Science
• Neuroscience
• Electronics

Background:

• Organic artificial synaptic devices are crucial for energy-efficient computing but face challenges with polymeric semiconductors and ion degradation in small molecular semiconductors.
• Organic electrochemical transistors (OECTs) have shown inconsistent properties and performance degradation.

Purpose of the Study:

• To develop low-power, high-performance organic photoneuromorphic devices using a novel small molecular semiconductor and source-gated transistor (SGT) structure.
• To investigate the synaptic properties and photoresponsivity of these new devices.

Main Methods:

• Fabrication of organic SGTs (OSGTs) using an n-type small molecular semiconductor (BPE-PTCDI) doped with Rhodamine B (RhoB).
• Characterization of photoresponsivity, power efficiency, and synaptic behaviors under electrical and light stimulation.
• Analysis of charge transfer mechanisms and Schottky barrier modulation.

Main Results:

• OSGTs with RhoB exhibited high photoresponsivity (2.07 × 10^3 A W^-1) and significantly improved photoresponsivity per drive power (3.70 × 10^3 times higher than typical FETs).
• Achieved synaptic properties at low voltage (1 V) stimulation, demonstrating high paired-pulse facilitation and pulsed photo-synaptic properties.
• Demonstrated low-power operation due to Schottky barrier modulation and RhoB doping.

Conclusions:

• The developed OSGTs show promise for next-generation neuromorphic computing and low-power electronics.
• Potential applications include auxiliary electronics for glaucoma patients and light trauma treatment.
• The findings contribute to advancing organic electronics for improved human quality of life.