Dual‐Mode Learning of Ambipolar Synaptic Phototransistor Based on 2D Perovskite/Organic Heterojunction for Flexible Color Recognizable Visual System

Artificial intelligence vision systems (AIVSs) with information sensing, processing, and storage functions are increasingly gaining attention in the science and technology community. Although synapse phototransistor (SPT) is one of the essential components in AIVSs, solution-processed large-area photonic synapses that can detect and recognize multi-wavelength light are highly desirable. One of the major challenges in this area is the inability of the available materials to distinguish colors from the visible light to the near-infrared (NIR) light for single carrier (hole-only or electron-only) SPTs owing to lack of cognitive elements. Herein, 2D perovskite/organic heterojunction (PEA2 SnI4 /Y6) ambipolar SPTs (POASPTs) are developed via solution process. The POASPTs can display dual-mode learning process, which can convert light signals into postsynaptic currents with excitement/inhibition modes (hole-transporting region) or inhibition/excitement (electron-transporting region). The POASPTs exhibit high responsivity to visible light (104 A W-1 ) and NIR light (200 A W-1 ), and effectively perform learning and memory simultaneously. The flexible POASPT arrays can successfully recognize the images of different colors of light. This study reveals that the fabricated POASPTs have great potentials in the development of large-area, high-efficiency, and low-cost AIVSs.