Unraveling the Mechanism of the Light-Triggered Synaptic Plasticity in Organic Photoelectric Synaptic Transistors

Light-triggered synaptic plasticity (LTSP) induced by electron trapping in organic photoelectric synaptic transistors (OPSTs) offers potential prospects in neuromorphic wearable artificial intelligence. However, a consistent and universal comprehend for LTSP behaviors especially on oxygen effect in OPSTs is still a critical challenge hindering their practical applications. A mechanism on strong dependency between the oxygen-induced and polar-group electron trapping in OPSTs, is successfully unveiled in this study for the first time. And the interaction between the oxygen and polar dielectric interface can be enhanced by properly modulating the specific surface area of thin-film semiconductors. This effectively binds the oxygen near conducting channel and further improves the trapping efficiency for photogenerated electrons, undergoing the time-dependent photocurrent generation and subsequent prolonged decay, forming the typical LTSP behaviors. These experimental demonstrations differ from previous reports and therefore may contribute an innovative perspective in the design of functional layers for high-performance OPST devices. A mechanism on strong dependency between the oxygen-induced and polar-group electron trapping in organic photoelectric synaptic transistors, is successfully unveiled for the first time, by regulating oxygen concentration, specific surface area, and insulation polarity. This likely provides an original perspective on the design of high-performance synaptic devices in burgeoning wearable artificial intelligent and retinomorphic vision.image