Owing to its unique optical and electronic characteristics, two-dimensional MoS2 has been widely explored in the past few years. Using first-principle calculations, we shed light on that the substitutional doping of Co can induce the half-filled intermediate states in the band gap of monolayer MoS2. The calculated absorption spectrum presents an enhancement of the low-energy photons (0.8 eV–1.5 eV), which is desired for intermediate-band solar cells. When the doping concentration increases, the reflectivity of the infrared and visible light (0.8 eV-4.0 eV) reduces, resulting in an improved photovoltaic efficiency of the material. Our results shed light on the application of heavily Co-doped MoS2 as intermediate band solar cell material.
