Browsing by Author "Bereket Fekede"

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    Investigation of 2D Hexagonal Transition Metal Dichalcogenide Heterostructures for Photocatalytic Water Splitting and Photovoltaic Solar Cells Using Density Functional Theory
    (Addis Ababa University, 2025-03) Bereket Fekede; Goergis Alene (PhD)
    Advances in materials science and technology are critical to the development of different sophisticated processes. It is imperative to recognize the significance of affordable, sustainable, and eco-friendly energy alternatives. Significant scientific and technological interest has consistently been shown in the use of hydrogen-based technologies towards the provision of clean, green energy in the energy mix. The formation of heterostructures combining MoS2, WS2, and ReS2 is a promising strategy in developing 2D semiconductor-based photo-catalysts for water splitting. This specific Research paper involves theoretical simulations to predict and optimize the properties of MoS2, WS2, and ReS2 heterostructures. This approach helps in understanding the fundamental mechanisms at play and designing more effective photo-catalytic systems. Monolayers and heterostructure combining MoS2, WS2, and ReS2 is constructed and investigated in this study using Density functional study as implemented in quantum ESPRESSO and CASTEP. ReS2 -WS2 hetero structure is type II hetero junction which has greater energy level than that of WS2 monolayer. It is also demonstrated appropriate CBM position located within -2.650 to -4.010eV range according to the band alignment, highlighting another class of suitable materials for hydrogen evolution reaction. In similar manner, hetero structure ReS2-MoS2 has greater energy level than MoS2 monolayer. The band alignment is shows us appropriate CBM position located within -3.054 to -4.350 eV range, this denote this hetero structure is suitable for hydrogen production. The power conversion efficiency of MoS2, WS2 and MoS2 –WS2 heterostructure is computed, and the results exhibit high efficiency with values of 18.7%, 17.0% and 21.4%, respectively making these materials promising for photovoltaic solar cell.