The interlayer coupling modulation of a g-C3N4/WTe2 heterostructure for solar cell applications

Theoretical prediction of the electronic structure, optical properties and contact characteristics of a type-I MoS2/MoGe2N4 heterostructure towards optoelectronic devices

Recently, the combination of two different two-dimensional (2D) semiconductors to generate van der Waals (vdW) heterostructures has emerged as an effective strategy to tailor their physical properties, paving the way for the development of next-generation devices with improved performance and functionality. In this work, we designed an MoS2/MoGe2N4 heterostructure and explored its electronic structures, optical properties and contact characteristics using first-principles calculations. The MoS2/MoGe2N4 heterostructure is predicted to be energetically, thermally and dynamically stable, indicating its feasibility for experimental synthesis in the future. The MoS2/MoGe2N4 heterostructure forms type-I band alignment, suggesting that it can be considered as a promising material for optoelectronic devices, such as light-emitting diodes, and in laser applications. Furthermore, the type-I MoS2/MoGe2N4 heterostructure has enhanced optical absorption in both the visible and ultraviolet regions. More interestingly, the electronic properties and contact characteristics of the MoS2/MoGe2N4 heterostructure can be tailored by applying in-plane biaxial strain. Under the application of compressive and tensile strains, transformations between type-I and type-II band alignments and between semiconductor and metal can be achieved in the MoS2/MoGe2N4 heterostructure. Our findings could provide useful guidance for experimental synthesis of materials based on the MoS2/MoGe2N4 heterostructure for electronic and optoelectronic applications.

A comprehensive review on the boosted effects of anion vacancy in the heterogeneous photocatalytic degradation, part I: Focus on sulfur, nitrogen, carbon, and halogen vacancies

The greenest environmental remediation way is the photocatalytic degradation of organic pollutants. However, limited photocatalytic applications are due to poor sunlight absorption and photogenerated charge carriers' recombination. These limitations can be overcome by introducing anion vacancy (AV) (O, S, N, C, and Halogen) defects in semiconductors that enhance light harvesting, facilitate charge separation, modulate electronic structure, and produce reactive radicals. In continuing part A of this review, in this part, we summarized the recent AVs' research, including S, N, C, and halogen vacancies on the boosted photocatalytic features of semiconductor materials, like metal oxides/sulfides, oxyhalides, and nitrides in detail. Also, we outline the recently developed AV designs for the photocatalytic degradation of organic pollutants. The AV creating and analysis methods and the recent photocatalytic applications and mechanisms of AV-mediated photocatalysts are reviewed. AV engineering photocatalysts' challenges and development prospects are illustrated to get a promising research direction.

Computational mining of GeH-based Janus III-VI van der Waals heterostructures for solar cell applications

The asymmetrical group III-VI monolayer Janus M₂XY (M = Al, Ga, In; X ≠ Y = S, Se, Te) have attracted widespread attention due to their significant optical absorption properties, which are the potential building blocks for van der Waals (vdW) heterostructure solar cells. In this study, we unraveled an In₂STe/GeH vdW heterostructure as a candidate for solar cells by screening the Janus M₂XY and GeH monolayers on lattice mismatches and electronic band structures based on first-principles calculations. The results highlight that the In₂STe/GeH vdW heterostructure exhibits a type-II band gap of 1.25 eV. The optical absorption curve of the In₂STe/GeH vdW heterostructure indicates that it possesses significant optical absorption properties in the visible and ultraviolet light areas. In addition, we demonstrate that the In₂STe/GeH vdW heterostructure shows high and directionally anisotropic carrier mobility and good stability. Furthermore, strain engineering improves the theoretical power conversion efficiency of the In₂STe/GeH vdW heterostructure up to 19.71%. Our present study will provide an idea for designing Janus M₂XY and GeH monolayer-based vdW heterostructures for solar cell applications.