Application Strategies of MXenes in Photodetector: Dual Perspectives of Acting as Modifiers and Being Modified

Photodetectors, as essential devices for photoelectric conversion, are critical to advancing military, industrial, and civil technologies. In the post-Moore era, the demand for extreme miniaturization and multifunctionality has driven intense research into low-dimensional materials. Two-dimensional MXenes have attracted considerable attention due to their exceptional conductivity, controllable surface functional groups, and tunable bandgap associated with surface terminals. However, the lack of systematic analysis on how MXenes enhance photodetector performance, modification mechanisms, and the multifunctional applications of modified MXenes constrains progress in this field. Herein, this review focuses on the dual roles of MXenes as performance modifiers and modifiable materials in photodetectors. It systematically examines the preparation and modification strategies of MXenes. Emphasis is placed on their potential as conductive electrodes, carrier transport layers, and heterojunctions with photosensitive layers to optimize device performance. The impact of advanced modification techniques on MXene properties is also explored, along with their subsequent application in photodetectors with enhanced sensitivity and stability. Additionally, emerging opportunities for MXenes in enabling novel device architectures and multifunctional photodetection platforms are highlighted. Herein, strategic guidance is provided for photodetector structural design and material innovation and establishes a foundation for next-generation optoelectronic devices and broader MXene integration in photonic technologies.