Oxide Based Pentachromatic‐Vision Inspired Optoelectronic Synaptic Transistor with Large Conduction States Over 512

Abstract Optoelectronic neuromorphic devices based on oxide semiconductors have been potentially investigated to mimic the functions of human visual synapses. However, the challenge comes from the wide bandgap characteristics of numerous oxide semiconductors, which restricts the response range of the device under ultra‐violet (UV) region. Strategies for widening the response range are mostly focused on artificially generating the defect states, however, most of them results in mimicking the tetrachromatic visual system from UV to visible light range. To be used for industries such as robotics, or autonomous vehicles, mimicking the tetrachromatic vision system should be overcome up to near‐infrared (NIR) region. Here, a facile solution processed indium‐gallium‐zinc‐oxide and silver oxide structured optoelectronic synaptic transistor is fabricated not only to mimic the function of human synapses, but to overcome the tetrachromatic human visual system up to the NIR region. The device not only showed photoresponse characteristics under the entire 405 to 830 nm wavelength region, but also showed significant synaptic behaviors with over 512 conduction states under a reasonable incident light power density of 4.5 mW cm⁻². The results will offer a useful facile method for fabricating optoelectronic synaptic transistors that can overcome the tetrachromatic vision systems.