Organic Heterojunction Phototransistors with Bi‐Directional Photoresponse for Vision Biomimetics

Abstract The scientific community is very interested in artificial visual perception systems because of their neuromorphological capabilities, such as image recognition, learning, and memory. This study reports on an organic heterojunction ambipolar transistor with PTCDI‐C₈/C₈‐BTBT/PTCDI‐C₈ sandwich structure. The proposed transistor efficiently transports both holes and electrons, with a current‐on‐switch ratio of ≈10⁶. Furthermore, hole or electron carrier transmission mechanisms are constructed to achieve the controllable adjustment of bi‐directional photoresponse under identical light illumination conditions by adjusting the gate voltage (positive photoresponse for V_g = 30 V and negative photoresponse for V_g = −30 V). The basic synaptic behaviors are simulated under light illumination, and the power consumption of the device is 18.51 fJ per synaptic event, which is comparable to the energy required for biological synapses. Finally, the simulation of human visual adaptation is completed using the bi‐directional photoresponse effects of the organic heterojunction phototransistor array, which provides a novel idea for neuromorphic visual simulation.