Department Of Physics

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Author: search.filters.author.Kumar, AshokSubject: search.filters.subject.2D materials

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    Optoelectronic and photocatalytic properties of stable pentagonal B2S and B2Se monolayers
    (Elsevier B.V., 2022-06-01T00:00:00) Katoch, Neha; Kumar, Jagdish; Kumar, Ashok; Ahluwalia, P.K.; Pandey, Ravindra
    Boron-based 2D monolayers have attracted tremendous interest due to their unique physical and chemical properties. In this paper, we report novel pentagonal monolayers, B2S and B2Se, which are predicted to be energetically, dynamically, and thermally stable based on density functional theory. At the HSE06 level of theory, they exhibit a moderate indirect bandgap of (e.g., 1.82 eV for Penta-B2S and 1.94 eV for Penta-B2Se). Strain-induced indirect-to-direct bandgap transition, high hole mobility (~103 Cm2V-1S-1) and strong optical absorption (? ~105 Cm-1) in the visible region are observed for these monolayers. Moreover, the electronic band structures and optical spectra are tunable by mechanical strains suggesting their visible light-harvesting capabilities for optoelectronic applications. In this way, the pentagonal family of 2D materials is now expanded to include boron-containing photocatalytic materials for water splitting applications. � 2022
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    Engineering 2D Materials for Photocatalytic Water-Splitting from a Theoretical Perspective
    (MDPI, 2022-03-21T00:00:00) Jakhar, Mukesh; Kumar, Ashok; Ahluwalia, Pradeep K.; Tankeshwar, Kumar; Pandey, Ravindra
    Splitting of water with the help of photocatalysts has gained a strong interest in the scientific community for producing clean energy, thus requiring novel semiconductor materials to achieve highyield hydrogen production. The emergence of 2D nanoscale materials with remarkable electronic and optical properties has received much attention in this field. Owing to the recent developments in highend computation and advanced electronic structure theories, first principles studies offer powerful tools to screen photocatalytic systems reliably and efficiently. This review is organized to highlight the essential properties of 2D photocatalysts and the recent advances in the theoretical engineering of 2D materials for the improvement in photocatalytic overall water-splitting. The advancement in the strategies including (i) single-atom catalysts, (ii) defect engineering, (iii) strain engineering, (iv) Janus structures, (v) type-II heterostructures (vi) Z-scheme heterostructures (vii) multilayer configurations (viii) edge-modification in nanoribbons and (ix) the effect of pH in overall watersplitting are summarized to improve the existing problems for a photocatalytic catalytic reaction such as overcoming large overpotential to trigger the water-splitting reactions without using cocatalysts. This review could serve as a bridge between theoretical and experimental research on next-generation 2D photocatalysts. � 2022 by the authors. Licensee MDPI, Basel, Switzerland.