Mxenes/WSSe heterojunction photodetector with ultrahigh sensitivity and accuracy

• Zr 2 CO 2 /WSSe heterojunction has ultrahigh photocurrent (47.02 a 0 2 /photon). • Mxene/WSSe heterojunction has obvious absorption peak in visible light region. • Mxene/WSSe heterojunction has the Gibb free energy change that tends to zero. Density functional theory is used in this work to examine the photoelectric properties of the Hf 2 CO 2 /WSSe and the Zr 2 CO 2 /WSSe. The calculation results show that these heterojunctions have significant peaks of absorption in the visible region compared with intrinsic materials, indicating that they can effectively capture visible light. Furthermore, the change of Gibbs free energy tends to zero, which is beneficial to the spontaneous reaction of electrocatalytic water splitting to produce H 2 . Interestingly, by calculating photocurrent, we found that the maximum photocurrent of the Hf 2 CO 2 /WSSe reached 14.09 a 0 2 /photon, and that of the Zr 2 CO 2 /WSSe up to 47.02 a 0 2 /photon, which showed extremely high photoelectric response sensitivity, making Hf 2 CO 2 /WSSe and the Zr 2 CO 2 /WSSe can be used to design high-performance photodetector.