Tunable Electronic Structure of Two-Dimensional MoX₂ (X = S, Se)/SnS₂ van der Waals Heterostructures

Abstract

Two-dimensional (2D) van der Waals heterostructures formed by stacking two different 2D materials have gained immense attention as they have the potential to show interesting properties. Herein, we report the detailed electronic structure of recently synthesized MoS2/SnS2 and MoSe2/SnS2 heterostructures obtained through density functional calculations. Our study shows that the MoS2/SnS2 heterostructure has a type-I band alignment with an indirect band gap, while MoSe2/SnS2 exhibits a type-II band alignment with a direct band gap. In type-II MoSe2/SnS2 heterobilayers, the hole and electron charge carriers are localized on two different 2D layers and thus show spatial charge separation, which lowers electron–hole recombination and prolongs carrier lifetime; thus, they are useful candidates for solar cell applications. Both the heterostructures MoS2/SnS2 and MoSe2/SnS2 retain their type-I and type-II band alignments, respectively, under applied uniaxial strain (both tensile and compressive). Moreover, both the heterostructures show excellent optical absorption (105 cm–1) in the entire UV–visible range. The robust type-I and type-II band alignments as well as strong optical absorption indicate that the two heterostructures studied may have good prospects in optoelectronic and photovoltaic applications.

Arene and functionalized arene based two dimensional organic–inorganic hybrid perovskites for photovoltaic applications

“…To investigate the light harvesting performance of the halide perovskite systems, we have herein calculated the optical absorption coefficient ( α ( ω )) by using the following equation 43–45 : where ɛ 1 ( ω ) and ɛ 2 ( ω ) are the real and imaginary part of the dielectric function, respectively. The complex dielectric function ɛ = ɛ 1 ( ω ) + i ɛ 2 ( ω ) is used to calculate the optical properties of a system.…”

Lead Free Two-Dimensional Mixed Tin and Germanium Halide Perovskites for Photovoltaic Applications

“…To investigate the light-harvesting performance of the perovskite systems, we have calculated the optical absorption coefficient (α­(ω)) using the following equation: − where ε 1 (ω) and ε 2 (ω) represent the real and imaginary part of the dielectric function, respectively, and are discussed in detail in the Supporting Information. For comparison, the optical absorption spectra of CH 3 NH 3 SnI 3 , CH 3 NH 3 Sn 0.75 Ge 0.25 I 3 , and CH 3 NH 3 Sn 0.50 Ge 0.50 I 3 perovskites are calculated.…”

Tuning the Electronic and Optical Properties of the ZrS2/PtS2 van der Waals Heterostructure by an External Electric Field and Vertical Strain

“…As it can be observed that the VBM is contributed from PtS 2 and CBM is contributed from ZrS 2 , so it can be concluded that the VBM and CBM of the heterostructure are a feature of two different layers. It shows that the ZrS 2 /PtS 2 heterostructure forms a type-II band alignment. , This type of band alignment offers an opportunity to separate electron–hole pair spontaneously which is useful for solar energy conversion and photocatalytic applications.…”

“…It shows that the ZrS 2 /PtS 2 heterostructure forms a type-II band alignment. 29 , 30 This type of band alignment offers an opportunity to separate electron–hole pair spontaneously which is useful for solar energy conversion and photocatalytic applications.…”