Opto-Electrochemical Synaptic Memory in Supramolecularly Engineered Janus 2D MoS₂

Area of Science:

• Materials Science
• Neuroscience
• Computer Engineering

Background:

• Artificial synapses are crucial for brain-like computing, requiring high integration density, energy efficiency, and fast data processing.
• Hybrid materials offer a route to encode both short-term potentiation (STP) and long-term potentiation (LTP) in synaptic devices.
• Developing complex synaptic functionalities in a single device remains a significant challenge.

Purpose of the Study:

• To develop a novel Janus 2D material for artificial synapses capable of independent signal processing.
• To achieve both short-term potentiation (STP) and long-term potentiation (LTP) within a single synaptic device.
• To explore the interplay of electrochemical and optical stimuli for enhanced synaptic functions.

Main Methods:

• Asymmetric functionalization of 2D molybdenum disulfide (MoS2) with ferrocene (Fc)/ferrocenium (Fc+) redox couple and photochromic azobenzene (Azo).
• Utilizing electrochemical stimuli to control Fc/Fc+ doping and adsorption/desorption on MoS2, steering between STP and LTP.
• Employing optical stimuli to activate azobenzene photoisomerization, inducing dipole-driven doping and modulating LTP.

Main Results:

• Demonstrated independent control over STP and LTP by varying electrochemical stimulus magnitude.
• Achieved LTP modulation through optical activation of azobenzene, leading to dipole-induced doping.
• Successfully boosted LTP to 4-bit (16 memory states) while maintaining STP functionality through combined stimuli.

Conclusions:

• The novel Janus 2D material effectively integrates multiple signal processing strategies for advanced artificial synapses.
• The hybrid approach combining electrochemical and optical stimuli offers a powerful pathway for high-performance brain-like computing.
• This work paves the way for energy-efficient, high-density synaptic devices with complex memory capabilities.