Strategy Toward Semiconducting Ti₃C₂T_x‐MXene: Phenylsulfonic Acid Groups Modified Ti₃C₂T_x as Photosensitive Material for Flexible Visual Sensory‐Neuromorphic System

Abstract The excellent electronic and electrochemical properties make 2D MXenes suitable candidates for sensors, batteries, and supercapacitors. However, the metallic‐like behavior of MXenes hinders their potential for optoelectronic devices such as photodetectors. In this study, the band gap of metalloid Ti₃C₂T_x MXene is successfully opened to 1.53 eV with phenylsulfonic acid groups and realized a transistor and high‐performance near‐infrared photodetector array for a flexible vision sensory‐neuromorphic system. The phenylsulfonic acid groups modified Ti₃C₂T_x MXene (S‐Ti₃C₂T_x)‐based flexible photodetector has a maximum responsivity of 8.50×10² A W⁻¹ and a detectivity of 3.69×10¹¹ Jones under 1064 nm laser irradiation. Moreover, the fabricated flexible vision sensory‐neuromorphic system for image recognition realizes a high recognition rate >0.99, leading to great potential in the field of biological visual simulation and biomimetic eye. Besides conventional devices with Au as the conductive electrodes, all Ti₃C₂T_x MXene‐based devices are also fabricated with S‐Ti₃C₂T_x as the photosensitive material and unmodified Ti₃C₂T_x as the conductive electrodes, exhibiting comparable optoelectronic performances.