Janus MoSO and MoSSe Monolayers: A Promising Material for Solar Cells and Photocatalytic Applications

The optoelectronic properties and device absorption efficiencies of MoSO and MoSSe Janus monolayer have been investigated using the first‐principles calculations. It is revealed that the MoSO and MoSSe possess a semiconducting behavior with a bandgap of 1.61 eV (indirect) and 2.00 eV (direct), which is ideal for effective light absorption. The device absorption efficiency of the MoSO and MoSSe family has been calculated for the first time and it is found that this family has strongest absorption (90%) ranging from infrared to ultraviolet region of the light spectrum. Furthermore, they are an ideal contender for the top cell in tandem design due to their broader bandgap and high device absorption efficiency. This family also keeps a suitable band edge alignment with the water redox potentials. Thus, strong absorption efficiency and desirable photocatalytic property for splitting water make MoSO and MoSSe an efficient candidate for optoelectronic devices, photocatalysis, and solar cell applications. It is found that MoSO and MoSSe possess an indirect (1.62 eV) and direct (2.00 eV) bandgap, respectively. The calculated device absorption efficiency of solar cells with a single layer of Janus MoSO and MoSSe reaches nearly 90% in the visible and UV. Because of their larger bandgap and high device absorption efficiency, MoSO and MoSSe are promising for the top cell in tandem architectures.