Ti ₃C ₂T _x, as one of new two-dimensional materials MXene, has abundant surface functional groups (—OH, —F, and —O, etc.) and can exhibit semiconductor properties through further surface functionalization. In addition, it has excellent absorption capabilities for both infrared and visible light. Currently, there is limited research on applying the semiconductor properties of Ti ₃C ₂T _xto infrared photodetectors. In this study, a self-driven near-infrared photodetector based on a C ₁₄H ₃₁O ₃P-Ti ₃C ₂/Au Schottky junction is developed. The modified C ₁₄H ₃₁O ₃P-Ti ₃C ₂two-dimensional semiconductor is prepared by a simple solution method, in which the phosphonic acid group reacts with the hydroxyl group on the Ti ₃C ₂T _xsurface. The C ₁₄H ₃₁O ₃P-Ti ₃C ₂/Au photodetector is constructed by using a drop-coating method at room temperature. The observation of an S-shaped curve in the I- Vcharacteristics indicates the formation of a Schottky junction between C ₁₄H ₃₁O ₃P-Ti ₃C ₂nanosheets and the Au electrode. The device exhibits good detection performance in the near-infrared band (808–1342 nm), with a maximum responsivity of 0.28 A/W, a detectivity of 4.3×10 ⁷Jones and an external quantum efficiency (EQE) of 32.75% under 1064 nm infrared light illumination. The I _on/ I _offratio is 10.4, which is about 7.3 times higher than that under 1342 nm light. The response time and the recovery time of the device are 0.9 s and 0.5 s, respectively. After 10 cycles of I- t, the photocurrent does not show any significant decay, indicating excellent repeatability and cycle stability of the device. Owing to the built-in electric field formed by the Schottky junction, photo-generated electrons and holes can quickly separate and produce photocurrent in the external circuit without the need for external voltage driving. In addition, the C ₁₄H ₃₁O ₃P-Ti ₃C ₂film obtained by drop-casting on Au is composed of several layers of nanosheets that are randomly stacked, which can effectively relax the plasma momentum limitation, promote the generation of hot electrons, and contribute to the photocurrent. As the C ₁₄H ₃₁O ₃P-Ti ₃C ₂/Au Schottky junction photodetector possesses self-driven characteristics and simple fabrication process, it exhibits great potential applications in detecting weak light signals, such as in the fields of astronomy and biomedical science. The successful fabrication of this photodetector provides a new approach for designing and developing MXene-based near-infrared detectors, thus promoting further advancements in this field.