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As a typical hetero-MXene, Ti3CN MXene has attracted great attentions owing to its ultrafast carrier dynamic and unique nonlinear optical response. However, the photo-response of pristine Ti3CN is unsatisfied due to the fast carrier recombination. Herein, multi-layer Ti3CN MXene is modified with well-dispersed Bi quantum dots, where the Ti3CN@Bi heterojunction can not only tune the optical absorption but also introduce energy transfer channels. The built-in electric field endows Ti3CN@Bi self-powered response behavior and the performance can be further enhanced by tuning external conditions. As demonstrated, the Ti3CN@Bi-based photodetectors exhibit high photocurrent density (18.24 mu A cm(-2)) and excellent photoresponsivity (18.32 mA W-1). In addition, the device shows fast response and outstanding stability (0.002% for each cycle), holding great potentials for practical applications. Hence, this work not only highlights the broad prospects of MXene-based heterojunction, but also provides great value for other optoelectronic device applications.