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[Display omitted] • Large-area Bi 2 O 2 Se film composed of many single crystal nanosheets was synthesized. • The layered Bi 2 O 2 Se film features a sharp interface with the SrTiO 3 substrate. • Bi 2 O 2 Se photodetector exhibits excellent cycling stability and long-term stability. • Bi 2 O 2 Se photodetector displays good imaging capability and rapid light extraction. Two-dimensional (2D) materials have proven to be a highly promising candidate for applications in electronic and optoelectronic devices due to their attractive structure and properties. However, the micron-scale dimensions, random distribution on the substrate, and complex transfer processes of 2D materials inevitably cause difficulties in device integration, which limits practical applications in photodetection. Herein, high-quality 2D Bi 2 O 2 Se film (2×2 cm) composed of numerous single crystal nanosheets on SrTiO 3 substrate was prepared employing the chemical vapor deposition method. The layered Bi 2 O 2 Se film features a perfect atomic alignment free of lattice mismatch and a sharp interface with the SrTiO 3 substrate. Afterward, a broadband photodetector based on 2D Bi 2 O 2 Se film was directly constructed, which covered the ultraviolet, visible and infrared range from 365 to 940 nm and demonstrated a fast response speed of 32 ms and 44 ms, maximum responsivity and detectivity of 136 mA/W and 2×109 Jones. Importantly, fast on/off behavior for 100 cycles and reliable photoresponse after storage in air for 1 year confirmed the excellent cycling stability and air stability of the Bi 2 O 2 Se photodetector. Furthermore, the Bi 2 O 2 Se photodetector as a single point sensing pixel was capable to perform high-resolution imaging of "H, I, T" patterns. This research affirms the huge potential of Bi 2 O 2 Se photodetectors to perform as reliable multi-band detection units in complex systems. [ABSTRACT FROM AUTHOR]