Photoelectric IGZO Electric-Double-Layer Transparent Artificial Synapses for Emotional State Simulation

Here, a three-terminal optoelectronic synapse is simply fabricated based on chitosan (CS)/indium gallium zinc oxide (IGZO) with a combination of electrical and optical simulations, which successfully emulates the key features of biological synapses of learning and memory behavior, in particular the reproduction of the typical Hebbian spike-time dependence plasticity (STDP) rule and 2794.6% of the maximum paired-pulse facilitation (PPF) under electrical stimulation. Creating an analogy to device characteristics, more importantly, memory behavior was studied with changes of the human internal state (comfortable and uncomfortable) and the external environment stimuli (quiet and noise); this showed the best results, longest forgetting time and good memory effect, under a comfortable internal state and a quiet environment. Our results suggest that solution-gated IGZO-based electric-double-layer transparent phototransistor transistors could act as platforms for synaptic and human behavior simulation.