**6. Conclusions**

In this chapter, we focus on 2D NTMDs and their applications in the field of photodetectors. 2D NTMDs exhibit extraordinary structural, electronic and optical properties. Unlike conventional TMD materials, the emerging NTMDs with abundant d-electrons and strong interlayer electronic hybridization have broadband optical absorption and ultra-high mobility, which are promising in optoelectronics. Then we have discussed efficient and controllable synthesis methods for 2D NTMDs with high crystal quality and large scalability. Various NTMDs based photodetectors have been developed till now. We have witnessed their outstanding performance, including wide-spectral range, ultrafast response, self-power and anisotropy. With the development of the materials technology and device manufacturing technology, NTMDs will have great potential in practical optoelectronic applications.
