Surface Modification of Ti₃CN MXene and Their Enhanced Performance in Photodetection

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 µA 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.