Mimicking evasive behavior in wavelength‐dependent reconfigurable phototransistors with ultralow power consumption

Abstract

AbstractRetinal‐inspired synaptic phototransistors, which integrate light signal detection, preprocessing, and memory functions, show promising applications in artificial vision sensors. In recent years, it has been reported to construct heterojunction in phototransistors to realize positive photoconductance (PPC) and negative photoconductance (NPC) modulations, thereby achieving visible and infrared wavelength discrimination and various visual functions. However, relatively little attention has been paid to wavelength‐dependent switching and reconfigurability between two states (PPC and NPC), limiting further applications for complex simulations of biological visual functions. Here, a mixed organic–inorganic heterojunction synaptic phototransistor was constructed by integrating CsPbBr3 nanoplates (NPLs) with strong blue‐light absorption and poly(3‐hexylthiophene‐2,5‐diyl) (P3HT) with strong red‐light absorption. Compared with the three‐dimensional (3D) structure CsPbBr3 nanocubes (NCs), the two‐dimensional (2D) CsPbBr3 NPLs exhibited more efficient charge transfer with P3HT. Based on the individual optical absorption properties in organic–inorganic heterojunction, the device exhibited wavelength‐selective and reconfigurable behavior between PPC and NPC. A low power consumption of 0.053 fJ per synaptic event was achieved, which is comparable to a biological synapse. Finally, Drosophila's evasive behavior to food under red and blue light can be successfully demonstrated. This work demonstrates the future potential of synaptic phototransistors for visuomorphic computing.