Visible region absorption in TMDs/phosphorene heterostructures for use in solar energy conversion applications

Heterostructures of pristine black phosphorene (P) with transition metal dichalcogenides (TMDs) monolayers of MoS₂, MoSe₂, MoTe₂, WS₂, and WSe₂ are investigated using density functional theory based simulations. The results suggest that individual MoS₂, MoSe₂, MoTe₂, WS₂, WSe₂, and black phosphorene have high absorption in some portions of the visible region (∼390-430 nm) and in the entire ultraviolet (UV) region. All the heterostructures results into redshift phenomena where absorption peaks are seen to shift to lower energies of the spectrum. The absorption coefficient is seen to increase with the wavelength and appears to be shifted towards the red end of the spectrum. High absorption is also observed in the entire visible region (λ ∼ 410 to 780 nm) of the spectrum for all heterostructures. This high absorption in the desired visible range may find many potential applications for the heterostructure, such as in the fabrication of optoelectronic devices and solar cells. The refractive index and dielectric constant of the heterostructure are also calculated and are found to be in line with trends in dielectric constant. Furthermore, it is observed that most of the resultant heterostructures have type-II band alignment which is ideal for solar energy conversion and optoelectronic applications.