Cl-Terminated Mo_4/3B_2-x MBene-Modulated CsPbCl₃ Perovskite for Enhanced-Performance Self-Powered UV Photodetectors Enabling Efficient Large-Area Imaging

High-performance and long-term stability of perovskite-based ultraviolet photodetectors (UV PDs) are two critical prerequisites for their fully mature applications. The preparation of high-crystallinity perovskite films with controlled defect density and enhanced environmental resistance has emerged as an effective strategy to address this challenge. This study proposes the incorporation of a functionalized novel 2D material, Cl-terminated Mo_4/3B_2-x MBene (Mo_4/3B_2-xCl_z), to improve the quality of the CsPbCl₃ films. Mo_4/3B_2-xCl_z serves as an efficient permeation channel, facilitating the reaction between the precursor solutions and enhancing the crystallinity of the films. Furthermore, the surface terminations of Mo_4/3B_2-xCl_z establish a strong coupling effect with the uncoordinated Pb²⁺ ions while simultaneously passivating the chlorine vacancy. This dual functionality effectively reduces the trapstate density and enhances the stability of the perovskite films. Ultimately, the UV PD treated with Mo_4/3B_2-xCl_z achieves a responsivity of 1.1 × 10³ mA W⁻¹, a specific detectivity of 7.3 × 10¹² cm Hz^1/2 W⁻¹, along with a rapid rise/decay time of 0.53/0.48 µs under self-powered mode, demonstrating outstanding long-term stability and successful application in large-area imaging. This research offers significant insights into the functionalization of MBene and highlights its pivotal role in the development of high-performance PDs for advanced UV imaging applications.